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Clutch slave options for a GM T5

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Simon Austin Avatar
On the GT V8 build, I have a GM T5 from a 1988 Camaro purchased by the PO. He also purchased a bell housing from D&D (I believe but will confirm with him). The bell housing is installed on the Rover 3.5 with a spacer. I have learned that there are aftermarket slave cylinder kits for the Ford T5 but nothing for the GM T5.

The biggest difference between the two is how the clutch fork operates. As can be seen in the first photo, the pivot point for the GM fork is on the left. A Ford T5 bell housing has the pivot point on the right. This means that the GM slave cylinder is mounted ahead of the bell housing and pushes the rod rearward. The Ford slave cylinder is mounted behind the bell housing and pushes the rod forward.

The GM slave cylinder operation is similar to an original Rover SD1 which I have in my other BV8. The R&D for this project is to use an SD1 slave cylinder mounted on a suitable bracket and attach it to the clutch fork. As shown in photo 2, the original GM fork was cut down by the PO as it conflicted with the tunnel on the car. There should be enough metal left to connect the slave rod to the fork.

Photo 3 shows an SD1 slave cylinder in what could become the position for mounting. I'm looking for input on whether this is worth pursuing or what other options are available. I can't be the first owner to encounter this challenge.

Any and all advice is appreciated. I have no plans to use an HTOB. I've already installed a stock MGB clutch master cylinder which works very well with the SD1 slave cylinder.



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ex-tyke Avatar
ex-tyke Graham Creswick
Chatham, Ontario, Canada   CAN
1976 MG MGB
The obvious solution would be to use a 'pull type' slave cylinder.....Wilwood, for one, has them.

Simon Austin Avatar
Interesting. I'll have a look. I didn't know such a thing existed. This was easier using the LT77 gearbox...winking smiley



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ex-tyke Avatar
ex-tyke Graham Creswick
Chatham, Ontario, Canada   CAN
1976 MG MGB
Here's an example of a pull type setup - the rear rod , I believe, is anchored and the front rod draws back the fork.


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Simon Austin Avatar
Thanks Graham. I just found some videos online. I'll add these to the research. I'm interested to hear how others have got a slave cylinder to work.



"Speed costs........how fast you want to spend?"

V8MGBV8 Avatar
V8MGBV8 Carl Floyd
Kinggsport, TN, USA   USA
Been a number of them done over the years. Good bit of info over at BrititshV8.org

cdcollins1 Avatar
cdcollins1 Doug C
Kansas City, Missouri, USA   USA
1978 MG MGB
X2 on the willwood pull slave.

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Bob in Vancouver Avatar
Bob in Vancouver Bob Elwin
Vancouver BC, Canada   CAN
1968 MG MGC
1969 MG MGC GT
Simon,
I used the Wilwood 'pull' cylinder on my Ford V8/Ford T5 setup and mounted it in front of the clutch fork so that it pulled it forwards. It worked just fine except for not very long! It would start to leak so I would replace it and a year or so later the same thing would happen. After three or four attempts at making the system work, I gave up.
Perhaps the geometry I was using was just wrong - in effect, operating the cylinder backwards. Maybe others have had good longevity so it was not the products' fault but the installation.
I any event, just like many others, I made up a plate mounted to the side of the T5 and used a Midget (.875"winking smiley slave cylinder to push the release arm forwards. It has worked just fine for several years now.
The issue with the GM/Ford clutch release arms is the differing geometry, as you point out. It makes the Ford set up need much more throw (at a lower load per unit of travel) to release the clutch. This affects your M/C : S/C calculations - but seeing you are using all GM, you can probably just use something like MGB or TR6 sort of ratios. Good luck with your installation. Bob.

Richardtherodder Richard Mounce
British Columbia, Canada   CAN
I went with the stock MC and the stock slave, although my bellhousing is different from yours.

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Simon Austin Avatar
I read a few comments about the Wilwood slave's limited life. Looks like you confirmed that aspect, Bob.

The research continues. Thanks!



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ex-tyke Avatar
ex-tyke Graham Creswick
Chatham, Ontario, Canada   CAN
1976 MG MGB
Simon, You're not confined to Wilwood products. There are others: Howe, McLeod, Speedway, CNC and even OEM offerings (Like Nissan Skyline).
Query 'pull type clutch slave cylinders' on ebay and have a butchers at alternatives to Wilwood.

fast-MG.com Avatar
fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
Howe racing has an HTOB for the Camaro T5.


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Dave Headley, dba FAB-TEK offers full service race car parts and preperation for MGB & MGA race cars, SCCA and Vintage. Dave is a mechanical engineer and has raced MGBs since 1963.
Jim Blackwood Avatar
Jim Blackwood * BlownMGB-V8
Gunpowder Rd., USA   USA
Simon, if you know someone who can do a bit of heliarc welding for you there is a better way, though a bit more effort. It isn't that hard to convert your bellhousing to put the pivot on the other side and use an S10 fork. (got that from RockAuto) That allows the slave to be mounted to the rear face of the bellhousing, tucked up out of the way between the transmission mount lugs. I did this recently on a BOP bellhousing. You need a 13/16-16 tap which is available on ebay for around $16 currently and a Forstner bit to cut the counterbore (do that before drilling). Tap drill size is 3/4". You may want to build up the inside where the pivot goes first and you may have to extend the mounting surface for the slave a bit. Or you might luck out and not have to do either.

I also stuck my S10 fork in the press and straightened the middle of it a little bit to get more working clearance for the pressure plate, you may or may not need that.

I think I had a thread on here about my clutch tribulations, either here or over on BritishV8. It would have the specifics on the slave cylinder I used. Just a standard face bolted slave off something like a recent small pickup. Common, cheap, and standard fittings IIRC. I haven't posted the info about the new pivot bolt there yet but it is the OEM one just moved to the other side.

Jim

mgv8glen Avatar
mgv8glen Glenn Towery
Dover, Delaware, USA   USA
I have had problems with the "todays stuff" & I had to have something that worked! I used a Ford Mustang clutch fork, made a plate that bolted to the "long" trans to bell bolts were I could use the 2 nuts on the long bolts to hold the pivot ball plate in place. Stock MGB M/C & 1275 with 1 inch bore sleeved down to 3/4 bore, got the rubber puck from NAPA. (I could not find the .875 MGM slave, but I think it would work. The 1/4" plate I made to hold the slave has to be as close to the trans as possible & you still have to make a wrench up to bleed the slave cyl. (no room between the trans./ body hump & the slave/trans. I used a MGM 1500 slave cyl. line & had to bend the metal ends a bit to get it to fit & not hit/rub & I had to put the brass 90 deg. end that is used on the clutch M/C on the slave cyl. Hear is were a pic. is worth a 1000 words.


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mgv8glen Avatar
mgv8glen Glenn Towery
Dover, Delaware, USA   USA
I looked for more pics. but no got. I have built 2 of this type of set up 3 & 4 years ago & still running!

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