|Volvo 240 Hydraulic Clutch
|UPDATED: June 6, 2018 CONTACT|
|D O M A
I N S
|Let me back
up a bit
before getting to my hydraulic clutch stuff.
<<< This is the clutch I put into my 245 way back in 2004 when I first installed a T5 transmission into my old 245. It was custom made for me by Clutchnet in SoCal because nothing else they had in an 8.5 inch clutch would hold the torque of my 2.6 liter stroker motor.
The pressure plate was assembled using two
standard spring sets stacked
together. The result was a clutch with 3000 lbs of
force. It was later offered to the public by Clutchnet because it was such as
simple, reliable design. The friction disc I used was nothing
special. Simple organic type.
The reason I mention all this is because it will help you understand why this clutch had a tendency to stretch and snap clutch cables. And long before they would snap, they'd require nearly constant attention with adjustments because of all that stretching. Not good stuff.
I know someone who even went to the trouble of modifying his 240
clutch pedal to accept TWO clutch
So back a number of years ago when I installed the T5 trans in my 242, I went with the same clutch. 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 needed to upgrade to hydraulic.
This hydraulic upgrade was completed in 2011.<<< This is the Volvo 260 clutch master cylinder I used, Volvo PN 1205729, manufactured by Fag. It was used in manual trans 264s in North America and in all manual trans 240s 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 seems to be available from some high-dollar sources. You can find them used and I think rebuild kits are still available if you do.
Here's a source for a rebuilt one that was still available as of February 2018.
Centric PN 136.39000 at Rock Auto: http://www.rockauto.com/en/parts/centric,13639000,clutch+master+cylinder,1996
So then I needed a clutch hose and a slave cylinder. I was able
to locate a USED hose (shown). I also chose the
shown slave cylinder, which is from a 740. The parts in this photo are
all manual transmission 740
parts. Note the
different looking master cylinder. 740s used a master cylinder with a
remote reservoir. And the length of this master cylinder makes it loo long to
fit in a 240. The fender gets in the way of a long master
NOTE: The hose thread pitch in the Volvo master cylinder is 12 x 1.0 mm (M12x1.0). Same for the thread pitch in the 740 slave cylinder. If you decide to have a hose made by your local hydraulic hose shop, the original length is about 38 inches, but anything above about 30 inches will fit just fine.
The inner piston diameter for both the Fag master cylinder and 740 slave cylinder is 19 mm (0.75 inch).
|Building your own
An original Volvo clutch hose is not easy to find.
<<< This image is a banjo adapter that can be found on eBay or other places. It's thread size is M12x1.0 (12 x 1.0 mm) for the master cylinder and AN -3 for the hose. Optionally you can choose -4 AN hose, but these directions I will use -3 AN. Search for "Steel M12x1.0 to 3AN banjo fitting". Using a banjo fitting helps with a tight fitting master cylinder that has very limited room for the hose.
Between the two adapters, you can seek out a premade hose or build one yourself. A premade one can be 36 inches. If you buy the parts to build one, choose a hose that is rated for high pressure, such as this: https://www.pegasusautoracing.com/productselection.asp?Product=3260 Stainless Steel Braided PTFE Brake & Clutch Hose that can handle 3000 psi. You want it in -3 AN size and then you'll need -3 female hose ends, such as these: https://www.pegasusautoracing.com/productdetails.asp?RecID=4154 Pegasus PN 3261-3-00 straight 3AN hose end. You can find good instructions for assembling the hose on YouTube or find a hydraulic hose shop and have them build one for you.
Here's an adapter for the slave cylinder if you use the 740 type, which
also has M12x1.0 threads. Search for "Steel M12x1.0 to 3AN
You should use a brass sealing washer on the M12 side. If you can find one, I recommend a metal-bonded sealing washer shown below.
<<< This is a metal-bonded sealing washer. It has a rubber o-ring embedded in it. It's generally used when a flare fitting is not used, such as on the M12 end of this adapter. McMaster Carr 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. They can also be found at Pegasus Racing, called Stat-O-Seal Sealing Washers: https://www.pegasusautoracing.com/productselection.asp?Product=3245
As mentioned, a short master cylinder is important in a 240.
740 hose and slave cylinder are a perfect fit on the typical M46 bell
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. There are some early Volvo bellhousings that have a different configuration and use a different slave cylinder. This type can be seen in the below diagram. You're on your own with those since I have no useful info on that slave.
Here's a source for a rebuilt one that was still available as of February 2018.
Centric PN 136.39002 at Rock Auto: http://www.rockauto.com/en/parts/centric,13839002,clutch+slave+cylinder,2044
<<< And you'll need this external snap ring (AKA: external circlip, retaining ring) to keep the slave cylinder locked in the mount. It's Volvo PN 914463 (number for 740). Inside diameter is 30 mm (1 3/16 inch or 1.187 inch).
Be careful of this little PLASTIC END CAP on the slave cylinder push
If your clutch fork has a HOLE in it where this plastic piece pushes, you could experience a failure like I did.
It's awesome when this happens.
One second you have a working clutch. The next second, pedal goes to the floor!
<<< The plastic cap sheered off and the rod went right through the hole in the fork.
So I then drilled that hole out and installed a large socket head
(allen) bolt in there.
Now the end of that rod rests in the center of that socket head.
<<< One of these here.
<<< Here's a useful diagram showing hydraulic clutch components. Part descriptions listed below.
from a cable to hydraulic clutch requires that you have a
compatible bell housing.
<<< These TWO photos 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 the first pic) for a crank position sensor, which came on 1989 and later cars. That's not really important for this information. Just a bit of trivia.
necessarily need a bell housing that has an opening for a crank
sensor unless you're using an engine management system that requires
it. The important
thing is that the
bell housing has the second pivot
ball mounting hole for
a hydraulic clutch FORK. There are some early M46 bell
do not have this second mounting hole.
Here are two different 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.
Part numbers that should work: 3549983, 1220763.
<<< I found a used 260 hydraulic clutch pedal and fitted it into my existing manual trans pedal box.
A hydraulic pedal is a bit longer than the cable pedal because it mounts in different holes in the pedal box. The hydraulic pedal holes are higher and will already be in the pedal box.
Here is where the holes are for mounting the hydraulic pedal.
Here is another view of the above hydraulic pedal.
Finding one of these pedals wasn't too difficult. Parts like these can occasionally be found in the Turbobricks for sale section or by placing a wanted ad in the wanted section where lots of helpful 240 owners will see it: http://forums.turbobricks.com/
There are some Turbobricks threads in which people have made their own hydraulic pedals or modified a shorter cable type pedal to work as hydraulic. That sort of work was beyond my skills. There are some examples below.
<<< Here's one. More can be found at: http://forums.turbobricks.com/showthread.php?t=326370&page=6
Here's another. More can be found at: http://forums.turbobricks.com/showpost.php?p=5602991&postcount=11
Update 2017After about 6 years of light use, the Volvo 260 Fag master cylinder shown at left began to fail. The piston seal began leaking fluid when under pressure.
This may have more to do with the heavy 3000 lb. clutch, but it could also have happened because it was a 30 plus year old NOS master cylinder when I bought it new. I could have decided to rebuild it, but I thought the chances of it holding up to my heavy clutch were not great. So I decided to try a different master cylinder. There are a number of choices. I'ill show you a few I considered below.
Whichever master cylinder you choose, be sure to choose the correct inner piston size. Most aftermarket master cylinders will give you several size choices. The Fag pictured here has a 0.75 inch (19 mm) piston. That's the size I would be looking for (but if you read to the end, you'll find out I later changed my mind).
master cylinder like this one from Wilwood may be a good choice.
It's certainly short enough to fit in a 240. I did not care for the hose outlet being on top like how it's pictured here. It makes bleeding more difficult than something with a hose sloping downward. When bleeding a hose that rises above the master cylinder, air will get trapped in there. So when bleeding, it will be pretty much impossible to get that air out if you have someone pushing the pedal while you're under the car opening the bleed valve. It can be done with a power bleeder that has the ability to push a lot of fluid through the hose under pressure to overcome that big air bubble.
If I had chosen one like this, I think I would have put a 90 degree fitting on there or maybe a banjo fitting if it will fit.
A benefit of this master cylinder is that it offers an advertised stroke of 1.4 inches, which is longer than the 1.1 inch stroke for the Tilton shown below. That bit of info came in handy later. You'll see if you keep reading.
Here's a comparison photo of three master cylinders.
Left side: Original Volvo 260 Fag.
Middle: Tilton 75 Series. Definitely a compact one. Wilwood has a nearly identical model called Wilwood Compact.
Right side: Wilwood. This one is sadly too long to fit in a 240. It hits the fender and the outlet is on the end where the fender hits. Possibly it could fit if a banjo fitting was put on the end. I didn't try that, so I don't know.
|<<< I chose the Tilton 75 Series (this one has
Soon after getting it I discovered that there was an unexpected problem. There always is.
The 240 firewall sheet metal just above where the master cylinder hole is interferes with the reservoir. It's because the reservoir is positioned so far to the rear and very close to the mounting flange. Basically the reservoir hits the firewall before the mounting flange does. You can shake your head in disbelief all you want. Yes, It's true.
if there is room could have been a remote reservoir. My 240 did not
that when I was doing this work, however months after completing my
project I did find the below
a Wilwood compact master cylinder with a remote reservoir in a 240
build thread, so it seems it can be done.
<<< More on the thread this photo came from can be found at http://forums.turbobricks.com/showthread.php?t=335335.
|FIXING FIREWALL CLEARANCE:
solution for the Tilton master cylinder and reservoir I decided to use
would have been a 1/2
inch spacer shaped like the mounting
flange so I could move this thing 1/2 inch further from the firewall.
Such a spacer
did not exist when I was searching.
<<< So my solution was to use a couple 1/2 inch thick round spacers and some longer bolts I had on hand. There's one spacer shown in this photo. Not the most elegant solution, but it gets the job done just fine and mounting at the firewall is still very solid. Problem averted.
Then it was time to have a new hose made. I took the master and slave
cylinders down to a local hydraulic hose shop. Keep in mind that
most hose shops are used to making hoses for heavy equipment and they
may or may not be experienced with hot rod stuff.
The Fag Volvo 260 master and 740 slave both have a thread pitch of 12 x 1.0 mm. The new Tilton has 3/8-24 thread pitch, same as AN -3. The Tilton master came with a couple of adapter fittings. One was that double male brass -3 flare fitting in the photo. The hose shop had JIC fittings and hose on hand since that's what they used for making hydraulic lines. They ended up using that double male flare along with an adapter fitting they supplied stepping it up to AN -4 size to mate with a new hose end, a 45 degree JIC (-4) female swivel fitting that was crimped to -4 high pressure Golden21/ISO 3000 psi hose.
On the slave cylinder end the hose shop supplied a male JIC (AN -4) to metric (12 x 1.0 mm) adapter (with a metal-bonded sealing washer). That mates to the straight JIC female swivel fitting the shop crimped onto the other end of the hose.
Total length of the hose when completed was about 38 inches.
Cost was about $60.
<<< This is a metal-bonded sealing washer. It has a rubber o-ring embedded in it. It's generally used when a flare fitting is not used, such as on the M12 end of this adapter. 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.
This clutch rod needed some adjustment. For my use it
be shortened almost 1/2 inch compared to when it was used with the 260
master (even with the 1/2 inch spacers at the firewall). The
threads allow a small adjustment, but for the
adjustment I needed, that forward rod had to be shortened a small
(maybe 1/8 inch)
using a bench grinder.
Installation completed.<<< To those of you who didn't believe me that spacers were needed to fit this master cylinder/reservoir combo, have a close look at there photos. Yes, these show the master cylinder WITH spacers. The reservoir cap is almost touching the firewall. It does clear though.
believe the piston stroke for
the Volvo 260 Fag master cylinder is about
inches. The stroke for this
Tilton 75 Series master is only 1.1 inch. This presented an issue
in my car and it meant I was not getting as much pedal travel as
before. So the clutch wanted to engage 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.
version is the same. So I changed to
a Tilton 75 with 13/16 inch bore (the
fatter one on
the right side). I was a bit surprised to see the
body design. Adding that extra 1/16 inch bore adds about 17% more
the stroke. It's equal to increasing the stroke from 1.1 inches to 1.29 inches. That did
the trick for me.
If you can add to the info in this page, please email me. CONTACT
When it comes time to bleeding brake or clutch hydraulics, nothing
beats the Motive Power Bleeder.
I won one of these many years ago
in a Volvo Davis Meet raffle and it has served me well for years and
years. DIY bleeding with no need for a helper.
Perfect. About $50 for you if you aren't a lucky raffle winner.
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: http://forums.turbobricks.com/showthread.php?t=100636
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