Volvo 240 Hydraulic
Clutch and Stuff |
UPDATED: October 27, 2024 CONTACT |
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Let me BACK UP a bit before I get to
the hydraulic clutch info. This is the "heavier" or "stiffer" modified 8.5 inch clutch I put into my 245 way back in 2004 when I first installed the T5 transmission into behind 2.6 liter stroker. This clutch was "custom" made from Clutchnet in SoCal. It failed badly because it had major slipping in freeway gears under boost. So Clutchnet said "Oops, sorry." Then they made a new custom clutch that was a lot stiffer (below). |
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This new much heavier pressure
plate below was assembled using two standard spring
sets stacked together. A very simple idea that worked very well. The result was a clutch with 3000 lbs of clamping force. It was so successful that later Clutchnet began offering it to the public. The friction disc I used was nothing special. Simple stock organic type. The reason I mention all this is because it will help you understand why this heavy clutch had a tendency to stretch and eventually snap clutch cables. And long before a cable would snap, it would require adjustments often because of all that stretching. Not good stuff in the long run. |
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I know someone who had the same problem. He went to the trouble of modifying his 240 clutch pedal to accept TWO clutch cables. So back a number of years ago when I later installed the T5 trans in my 242, I went with the same clutch setup. I know there are better clutch setups available nowadays. Lots more cools stuff has become available over the years because of the increasing popularity of these cars. I'll get around to trying a better one someday. For now, this is what I have. So after a few snapped cables, I knew I finally needed to upgrade to hydraulic. THAT BEGINS BELOW |
Short intermission to mention why I didn't go with a
Tilton (style) Hydraulic Release Bearing. Here's a very lengthy TB discussion on this if you want more info. I don't have any of THIS in my page here. https://turbobricks.com/index.php?threads/tilton-hydraulic-release-bearing-and-t5-notes.357178/ So why didn't I try this? Reason #1: That release bearing was an unknown subject back when I did this conversion. Reason #2: I didn't want to be the one who posted this: "I had a lot of issues using these Tilton throwout bearings on Randy's flyin' moose car using M90 trans. We went back to the oem style and have never looked back." https://turbobricks.com/index.php?threads/tilton-hydraulic-release-bearing-and-t5-notes.357178/page-3#post-6373384 BACK TO THE TOPIC AT HAND Here are some CABLE CLUTCH diagrams from the 1981 New Car Features book. And here is a diagram for the HYDRAULIC CLUTCH (below). This image above suggests there is "no play to adjust" in case you need some adjustment. This is true with regard to the pedal, but there is always some adjustment available by spacing the clutch pivot ball closer to or further from the bell housing. The clutch pivot ball can be seen below CLICK HERE. 240 FIREWALL INFO Some firewalls have holes already, some do not. This is the driver side firewall plate from a 240. The large lower hole is where the steering column goes through. Most early 240s I've seen will have this type of plate, regardless of it coming with a manual or auto transmission. So converting an auto to manual or installing a hydraulic clutch master cylinder does not require altering the firewall if you have this plate. Some 240s, however, have a plate WITHOUT the clutch holes. Here's a 240 plate that came WITHOUT the hole for clutch controls. If you have a 240 like this, you can trying finding a different firewall plate, however swapping this plate can be very time consuming, especially since it requires removing the steering column. The other easier option is to drill a few holes. A template is not needed if you have a brake pedal box with a clutch pedal. For some perspective, here's what the CABLE TYPE CLUTCH PEDAL looks like. For a hydraulic clutch, the clutch pedal must be changed to a hydraulic type. Here we can see where the holes need to be for the clutch master cylinder. You can use the pedal bracket as a template to locate the holes and figure out precisely where to drill. |
My conversion from Cable to Hydraulic was completed in 2011.
INTRODUCTION OF THE 260 HYDRAULIC MASTER CYLINDER
This is the Volvo 260 clutch master cylinder I used, Volvo PN 1205729, manufactured by Fag. An aftermarket MC may be available as Centric PN 136.39000. It was used in the manual trans 264 in North America and in all manual trans 240 models in the UK and Australia because they were right hand drive. It was still available new when I started buying these parts in 2011. It still may be available. Or you might also find them used and I think rebuild kits are still available if you do. The inner bore/piston diameter is 19 mm (0.75 inch). The hose port on the rear is 12 x 1.0 mm Inverted Flare (double flare). This is quite different from the 10 mm Bubble Flare that Volvo used in all brake systems. It uses a metal hose like this photo below. |
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So then I
needed a clutch hose to mate the MC to a Slave Cylinder.
Back in 2011 I was able to locate a USED hose (like this one shown below). It had a hard line beginning at the master cylinder and it then transitioned to a flexible hose further down. I also chose the same slave cylinder seen in this first photo below. It was originally made for a 740, but it fits perfectly in the 240 since the bell housing is the same. Note the different looking clutch master cylinder below. That's a 740 MC, which used a clutch master cylinder without it's own reservoir. Instead this cylinder receives fluid from the brake MC reservoir, as you can see in the second photo below. The length of this 740 clutch master cylinder is longer than the Fag MC for a 240. I thought it might be difficult to fit in a 240 (until I later saw this second photo above of someone who did it in that 240). So use your judgement. The body of this 740 clutch master cylinder is longer than the 260 FAG MC, so it will be a fairly tight fit in a 240. The hard line should be made to turn quickly so it clears the strut tower. This 740 Clutch MC is known as Volvo PN 8601785 (also 1273680, 1330248, 1330249). The inner piston/bore is 19 mm (0.75 inch) for the master cylinder (same for the slave cylinder). Same bore as the 240 Fag MC. I have not found an official specification for the length of travel of this MC, but in 2023 this thread below revealed that it's 25 mm (1 inch), which is shorter than the 240 Fag MC: 33 mm (1.3 inches). https://turbobricks.com/index.php?threads/performance-clutch-master-slave-cylinder-riddle.370314/ CUSTOM HOSE: If you decide to have a custom hose made by your local hydraulic hose shop, the original length of the pictured hose above is about 38 inches, but anything above about 30 inches will fit just fine in a 240. |
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Building your own clutch hose. An original Volvo 264 hydraulic clutch hose will not be easy to find. This image above is a banjo adapter fitting which can be found online. It's thread size is 12 x 1.0 mm and it will fit the master cylinder outlet. It then uses the AN -3 end for the hose fitting. Search for "Steel M12x1.0 to 3AN banjo fitting". Optionally you can choose -4 AN hose, but for this info I will use -3 AN. Using a banjo fitting on the MC can help with a tight fitting master cylinder that has very limited room for the hose. Using adapters shown here you can either seek out a pre-made hose or build one yourself. A proper length can be 30 to 36 inches. If you buy the parts to build one yourself, choose a hose type that is rated for high pressure, such as this: https://www.pegasusautoracing.com/productselection.asp?Product=3260 or https://www.summitracing.com/parts/aer-fcc0303 These Stainless Steel Braided PTFE Brake & Clutch Hoses can handle 3000 psi. Here are some hose ends in -3 AN size: https://www.pegasusautoracing.com/productdetails.asp?RecID=4154. Pegasus PN 3261-3-00 straight 3AN hose end. |
THIS GUIDE WILL HELP IF YOU WANT A FLARED HARD LINE AT THE MASTER CYLINDER If you prefer a hard line like this below, you'll need to flare the pipe. So you'll need a flaring tool or someone who can flare brake line. This hard pipe is the same type of pipe as brake line, but normally this clutch line is larger than a typical 3/16 inch (4.75 mm) brake line you have one your 240, although you CAN use 3/16 inch if you like. A larger size pipe (shown below) can be 6 mm brake line. The flare type needs to be Inverted Flare (double flare), because that's what this MC requires. That hose fitting in this photo below is 12 x 1.0 mm for Inverted Flare (double flare). If you use 3/16 inch brake line, you can use this flare fitting fitting at the master cylinder (1 needed): https://www.belmetric.com/double-flare12x1df475.html. If using a larger 6 mm brake line, you can use this one (1 needed): https://www.belmetric.com/double-flare12x10df600.html. Then on the other end of the hard line, which should transition to a flexible line, you can use a similar fitting, except in my opinion this end should be flared as a bubble flare (which is used in Volvo brake lines). That would mean this fitting is used (if using 3/16 inch line) (1 needed): https://www.belmetric.com/bubble-flare12x10bf475.html. Or this one (if using 6 mm line) (1 needed): https://www.belmetric.com/bubble-flare12x10bf600.html. This fitting can then be mated to an adapter, which will adapt the 12 x 1.0 mm flare fitting to an AN -3 hose end. This one will do it (1 needed): https://www.summitracing.com/parts/cst-sbh8069. So then the flexible hose will be AN -3 high pressure hose like this: https://www.summitracing.com/parts/aer-fcc0303 with a hose end like this on each end (2 needed): https://www.summitracing.com/parts/aer-fbm1100. |
Here's a useful video showing how to assemble a hose like this. https://www.youtube.com/watch?v=5tdsgZ-KfWI |
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Here are some
adapters that will fit the 740 slave cylinder, which has M12x1.0 threads.
The hose side will use either AN -3 or AN -4
thread. You can search for "Steel M12x1.0 to 3AN adapter" or "Steel M12x1.0 to 4AN adapter".
Or something like this: https://www.summitracing.com/parts/ear-592053erl You should use a brass sealing washer on the M12 side (the side going to the slave cylinder). Or as a better option that I used, I suggest a metal-bonded sealing washer shown below. METAL BONDED SEALING WASHER This is a metal-bonded sealing washer above. It has a rubber o-ring embedded in it. A sealing washer is generally used when a flare fitting is not used, such as on the M12 end of this adapter above. McMaster Carr has these washers: https://www.mcmaster.com/#standard-washers/=1blhle3, click "Sealing Washers," then "Metric High-Pressure Metal-Bonded Sealing Washers." Your local hydraulic hose shop may have them too. They can also be found at Pegasus Racing, called Stat-O-Seal Sealing Washers: https://www.pegasusautoracing.com/productselection.asp?Product=3245 You might be thinking that hybrid washer above is inferior to an all-brass washer. You would be wrong. It can handle thousands of PSI and will easily out-perform the sealing capability of an all-brass washer. The custom clutch hose I had assembled in 2017 by a hydraulic shop can be seen a bit further below or CLICK HERE. |
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The 740 hose and slave cylinder are made to be a perfect
fit on the typical M46 bell housing.
The circular mount on an M46 (or M47) bell housing is designed to hold either the cable end or this slave cylinder. This slave is Volvo 740 PN 8601783 (older PN 6843913). It's still available from a number of sources. Be aware there are some very early (pre-B21F) Volvo bell housings that have a different configuration and use a different slave cylinder. You're on your own with that type slave, since I have no useful info on that. |
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This 740 slave cylinder has an outlet port that is threaded 12 x 1.0 mm. It's machined at the bottom for a bubble flare (different from the 240 FAG MC), so if you prefer, you can use a 12 x 1.0 mm Bubble hose end or adapter fitting. The face of the port is also machined flat, so you can optionally use a 12 x 1.0 mm fitting (or banjo) that accepts a sealing washer (brass, aluminum or metal-bonded sealing washer). The second photo below shows what the original hose end looks like for the 740 slave cylinder. The thread is 12 x 1.0 mm Bubble Flare. It's pictured next to a 10 mm 240 brake line for comparison. |
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And you'll need this
external snap
ring (AKA: external circlip, retaining
ring) to keep the slave cylinder locked in the
mount on the bell housing. It's
Volvo PN 914463 (part number for 740
part). Inside diameter is 30 mm (1
3/16 inch or 1.187 inch).
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CAUTION: Be careful of
this little PLASTIC END CAP on the Volvo slave
cylinder push rod.
If your clutch fork has a HOLE in it, as this one does pictured below, where the plastic end on the push-rod pushes, you could experience a failure like I did. |
One
minute you have a nice working clutch. The next
minute your pedal goes to the floor! Because of THIS.
The white plastic end cap sheered and the push-rod went right through the hole in the fork. |
So I then drilled that hole out in the fork and installed a large socket head (Allen head) bolt in there. Now the end of that rod rests in the center of that socket head. |
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Converting
from a cable to hydraulic clutch requires that you
have a compatible bell housing.
These TWO photos below show a later type M46 or M47 bell housing. One part that gives it away as a later type is the opening at the top of the bell housing (top-left in this first pic below) for a crank position sensor, which came on 1989 and later cars. That's not really important for this discussion. Just a bit of trivia. You won't necessarily need a bell housing that has an opening for a crank position sensor unless you're using an engine management system that requires it, such as LH 2.4. The important thing is that the bell housing should have the second pivot ball mounting hole for a HYDRAULIC CLUTCH FORK. There are some early (pre-240) M46 bell housings that do not have this second hydraulic mounting hole. |
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Here are some close-up images of the hole for the hydraulic pivot ball. There is more than one style of pivot ball. Below: One is short and one is tall. The threaded hole in the rear is M8-1.25. Volvo PN 6814409 (tall) is listed by Volvo Classic Restoration as for 1979-92 cars. https://classicvolvorestoration.com/p/pivot-pin-clutch-fork-240-79-92 Volvo PN 3549638 (short) is listed for 1993 and later cars. https://classicvolvorestoration.com/p/pivot-pin-clutch-fork-volvo-240-74094093 I think you could probably use either type. If it needs to be longer, a spacer or washer could be placed under it. |
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Comparison: Cable and Hydraulic Clutch Forks. The top clutch fork is a typical cable type. The bottom one is a typical hydraulic type from a 740. Any typical 740 clutch fork is perfect for this project. Volvo 740 part numbers that should work: 3549983, 1220763. |
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I found a used 260
hydraulic clutch pedal and fitted it into my
existing manual trans pedal box.
A hydraulic clutch pedal is about 50 mm longer than the cable pedal (between the pedal and pivot) because it mounts into a different set of holes in the pedal box. The hydraulic pedal holes are higher up. The holes will normally already be in the pedal box. My pedal box had the holes needed. |
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Here is where
the holes are for mounting the hydraulic pedal higher up.
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There are some Turbobricks threads in which
people have made their own hydraulic pedals or
they have modified a cable type pedal to work. That sort of work was beyond my
skills.
Here's a thread about one that was custom made: https://forums.turbobricks.com/showthread.php?t=326370&page=6
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As of May 2018 STS Machining is offering newly made aluminum hydraulic clutch pedals: https://www.stsmachininginc.com/products/240-hydro-clutch-ped |
After about 6 years of use, the new Volvo 260
Fag master cylinder shown here began to
fail. The piston seal began leaking fluid
out of the back when pushing on it.
This might have been due to the heavy clutch I had, but it could also be because this was a 30 plus year old NOS part when I bought it. I could have rebuilt it, but I thought the chance of this happening again was probably high. So I decided to try a different master cylinder. There are a number of choices. I'll show you a few I considered below. Whichever master cylinder you choose, be sure to consider the inner piston size. Most aftermarket master cylinders will give you several size choices. The Volvo Fag 260 MC has a 0.75 inch (19 mm) inner piston. That's the size I would be looking for initially (but if you read further down, you'll find out I later changed my mind for my clutch situation). |
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A master
cylinder like this one below from Wilwood may be a
good choice. It's certainly short enough to fit in a 240 and it's very similar to early Volvo master cylinders used in Amazons, however I did not prefer the hose outlet being on top like this. It makes bleeding more difficult than something with a hose sloping downward toward the slave cylinder. When bleeding a hose that rises above the master cylinder, air will get trapped in there. So when bleeding, it can be hard to get that air out if you have someone pushing the pedal while you're under the car opening a bleed valve. This can more easily be done with a power bleeder, which has the ability to push a lot of fluid through the hose under constant pressure to overcome that air bubble. If I had chosen one like the Wilwood above, I think I probably would have put a 90 degree fitting on the outlet for the hydraulic hose or maybe a banjo fitting similar to the below images. Here are a couple images above from Aris 240 (from Greece). In 2023 he installed this Wilwood 260-6089 master cylinder for his clutch. It's a remote reservoir style MC and it shares the brake fluid reservoir. Aris 240 build is detailed in the following forum post: https://turbobricks.com/index.php?threads/the-build-story-of-a-greek-hopefully-fast-240-brick.310632/page-7#post-6371397 A good benefit of this style of Wilwood master cylinder is that it offers an advertised stroke of 1.4 inches (35.5 mm). This is very close to the Volvo Fag 260 MC, which has a stroke of 1.3 inches (33 mm). The TILTON MC (below MIDDLE) only has a 1.1 inch (28 mm) stroke. This STROKE info became more important later for my car. You'll see if you keep reading. |
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When it came time to replace the Fag MC, I chose the Tilton
75 Series. This one has a .750 inch (19 mm)
piston. While installing it I discovered that there was a new problem. There always is, isn't there. The 240 firewall sheet metal (just above where the master cylinder mounts to the firewall) interfered with the reservoir. It's because the reservoir on this style master cylinder is positioned very far to the rear and you can see it's very close to the firewall mounting flange. Basically the reservoir hits the firewall before the mounting flange does. PHOTOS coming up further below. The outlet port is threaded for 3/8-24 female, same as AN -3 thread. |
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One solution for this firewall interference could be a remote reservoir. I didn't seriously think that was a good option, however after completing my project I found this photo above of a similar Wilwood compact master cylinder with a remote reservoir fitting. So it seems it's been done. More on the thread where this photo came from can be found at turbobricks.com/lm7-t56-into-a-82-245.335335. Or I could maybe have tried a 740 master cylinder to feed the clutch MC remotely. Again, I didn't know about this option until later. However this MC WOULD NOT have worked for my car. I later found out the stroke of this MC is too short for my use. So it's good I didn't try one. |
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FIXING THE FIREWALL
CLEARANCE ISSUE with SPACERS: So my solution was to use a couple 1/2 inch thick round spacers and some longer bolts I had on hand. Not the most elegant solution, but it gets the job done just fine and the mounting at the firewall is still very solid. Problem fixed. I had originally hoped to find a 1/2 inch spacer shaped similar to the mounting flange so I could move this master cylinder 1/2 inch forward. Such a spacer did not exist when I was searching and making one was too much work. |
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Then it was time to have the new hose made. I
took the master and slave cylinders down to a
local hydraulic hose shop, along with the adapters I had. Keep in mind that most hydraulic hose shops are there to hydraulic make hoses for heavy equipment. They may not be experienced with automotive or hot rod stuff. Some places are. There are a number of ways to make a hose for these components. Lots of options exist. If you know specifically what fittings YOU want, discuss that with them. Try to be patient and have as much info for them as possible. Hose detail: Tilton Clutch MC: The Fag-Volvo 260 MC I previously used and the 740 slave cylinder both have a thread pitch of 12 x 1.0 mm female. Now I have an MC with a completely different thread. This Tilton MC has 3/8-24 female threads, which is the same as AN -3. The port outer face is machined flat in case you want to use a banjo fitting or an AN -3 fitting which uses a sealing washer. Those are options to consider. I went a different route. The Tilton MC came with some adapter fittings. One was that gold-colored double male AN-3 flare fitting in the photo above. The hose shop I went to had commercial JIC fittings and high pressure -4 Golden21/ISO 3000 psi flexible hose. They used that gold AN -3 double male flare fitting along with another adapter fitting they supplied, which stepped up the AN -3 to AN -4. Then they mated a new hose end to the AN -4 hose. This new hose end was a 45 degree JIC (AN -4) female swivel fitting, which can be seen above. That completed the MC end. Hose detail: 740 Slave Cylinder: On the slave cylinder end the hose shop supplied a Male JIC 7/16-20 (equal to AN -4) to 12 x 1.0 mm O-Ring adapter, which is shown below. The 12 x 1.0 mm end goes into the clutch slave. The O-Ring I used was a metal-bonded sealing washer. The above adapter would then mate to a new hose fitting they crimped onto the AN -4 flexible hose. This new hose fitting was a JIC 7/16-20 (equal to AN -4) STRAIGHT female swivel fitting, which can be seen in the hose photo above. The total length of the new hose when completed was about 38 inches. Cost was about $60. |
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This is a metal-bonded
sealing
washer.
It has a rubber o-ring embedded in it. It's generally used where a flat sealing washer is required or when a flare fitting is not used, such as on the M12 end of this adapter above. McMaster Car has them: https://www.mcmaster.com/#standard-washers/=1blhle3, click "Sealing Washers," then "Metric High-Pressure Metal-Bonded Sealing Washers." Your local hydraulic hose shop may have them too. You might be thinking this hybrid washer above is inferior to an all-brass washer. You would be wrong. It can handle thousands of PSI and will easily out-perform the sealing capability of an all-brass washer. |
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This clutch push rod needed some
changes. For my use it needed to be shortened almost 1/2 inch compared to when it was used with the 260 master, even with the 1/2 inch MC spacers at the firewall shown above. The threads on this thing allow for a small adjustment, but for the adjustment I needed, that forward rod had to be shortened a small amount (maybe 1/8 inch) using a bench grinder. |
Installation
completed.
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ANOTHER Master Cylinder Change
Update: June 2017 I believe the piston stroke for the
Volvo 260 Fag master cylinder is about 1.3 inches (33 mm).
The Tilton 75 Series MC with 3/4 inch (19 mm) bore has a stroke of only 1.1 inch (27.94 mm). This presented a problem in my
car and it turned out I was not getting as much pedal
travel as before. So after installing the above Tilton MC, the clutch wanted to disengage
very close to end of the pedal travel near the
floor. I didn't like that. I needed a
bit more stroke, but the Tilton 75 master cylinder
is not available with a longer stroke.
The Wilwood version of this MC is the same. So I changed to a Tilton 75 with a larger bore SHOWN ABOVE, 13/16 inch (20.64 mm) bore. The new one is the fatter MC above. I was a bit surprised to see the difference in the much bigger body design. Adding that extra 1/16 inch (1.59 mm) to the bore adds about 17% more volume in the stroke. It's equal to increasing the stroke from 1.1 inches to 1.29 inches, which virtually gives it the same volume as the Volvo FAG master. That corrected the problem. If you can add to any info in this page,
please email me.
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MOTIVE POWER BRAKE BLEEDER
When it comes time to bleeding brake or clutch hydraulics, nothing beats the Motive Power Bleeder. I won one of these many years ago at a Davis Volvo Meet raffle and it has served me well for years and years. DIY bleeding with no need for a helper. Perfect. It's about $50 for those who aren't raffle winners.
RESOURCES:
AN Thread Wikipedia: https://en.wikipedia.org/wiki/AN_thread Automotive Fittings Explained: http://www.speedwaymotors.com/the-toolbox/automotive-fittings-explained/28780 Useful discussion treads: turbobricks.com/wilwood-clutch-master-cylinder-for-my-242.100636 turbobricks.com/making-your-cable-clutch-hyrdaulic-in-your-240.149175 turbobricks.com/240-hydraulic-clutch-conversion.234399 turbobricks.com/critique-my-hydraulic-clutch-set-up.325285 turbobricks.com/converting-cable-trans-to-hydraulic.320417 |
Fixing
a Bent or Mangled Clutch Pedal Box I had to do this twice! |