VD throw out bearing rebuild ‘90-96

[upnorthelan]

Hi All,

Firstly I apologize if there’s a thread on this topic. If so, I couldn’t find it. Only a more modern version of the Hewland.

My motor is out and I’ve heard this is a smart thing to do while I have access to it. I was able to pop out the slave “piston” (?) from the cylinder with compressed air and those seals where straight forward. It looks as though I also need to do 2 seals maybe for the body of the cylinder that might come out like a cartridge for lack of a better layman’s description?

I’m assuming the 4 small allen head bolts are my next step. The two and 3 and 9 o’clock came free easily, but the upper and lower bolts won’t come out so far. I’ve heated briefly and thunked a little, but do not want to strip those little allens. I’m not sure if I should proceed and potentially screw things up?

I also read that there are two brands of seals, one being superior? Mine are not labeled. I bought them through Pegasus.

Thanks for any advice,
Mike

p.s. the picture is rotated 90* for some reason:/

[JHerscher]

As I recall, the 2 allen head bolts at 3 & 9 o'clock are removed. Then the cylinder is jacked out by threading screws (probably 10-32) into the holes drilled at 12 & 6 o'clock. Thread them into the jacking holes evenly; you don't want it to get cockeyed.

Once out, clean everything well. Reassembly is straightforward. Use a quality rubber grease - the thin o-rings are easy to get nicked and in my experience the grease is more effective at preventing that than brake fluid.

Some put a thin layer of Ultra-RTV on the flange as an extra precaution.

There are devices that people have made that can allow you to test for leaks it before bolting it to the back of the engine. Or you can put it together and test it before everything is buttoned up and fluids in.

You are fortunate that the previous owner drilled and tapped the 12 & 6 o'clock holes. It is a royal PITA to get out if they are not there.

As far as I know, the two screws you mention are stuck do not matter in this rebuild. I think they are from when they drilled the fluid passages but I am probably wrong.

No comment on the o-ring kits. Been too many years for my opinion to matter.

John

[Steve Demeter]

I think if you look at the FF forum there is a fairly recent thread on this topic. Just a thought.

[upnorthelan]

Thanks John & Steve!

[Rick Kirchner]

IIRC, the dimensions of the standard British parts are off just a tad and thus prone to leaking. The O-ring kit from Taylor Race Engineering has a couple of the o-rings slightly oversized to fix this.

The biggest risk in putting the thing back together and back in is shaving an o-ring in the process. In putting the cylinder together I always use a generous amount of silicone grease and often heat the outer parts while freezing the inner parts - every little bit helps, as does a press and a couple soft pieces of wood so you don't goober up the aluminum.

The biggest risk is having the outer rear o-ring shaved by the two little inlet passages, which have razor sharp edges. If you can get in there with a very small fine abrasive ball and take the edge off of those it will help. don't forget to flush! Then again, lots of silicone grease.

I've also learned that after sitting for a winter don't get in and stomp the clutch. Try to get some heat in the oil so they can relax a bit from the set they take.

[upnorthelan]

Hi Again,

So after parenting duties, etc… I finally got the clutch cylinder jacked out. I’ll make a hollow wooden cylinder to help press it back in this week.

After reading a few threads I’m curious about the o-rings. One comment was about curing temps and recommended “epdm (iirc) vs. buna n.” Rick, you mention Taylor being oversized and better too. I bought my replacement set from Pegasus before I read that recommendation so I’ll call and ask Jay this week. I have time to get a better set if that’s the case.

Another question I have is upon pulling out the cylinder body I noticed a small amount of motor oil behind it (pic attached/ sideways for whatever reason). My bellhousing has 4x 7/8”ish holes drilled thru to the overflow rear portion. I’m curious if I need to somehow seal that the slave tube off somehow or if the slave cylinder outer rear o-ring provides that seal?

Thanks again for newbie help!
Mike

[Rick Kirchner]

The motor oil is likely from a leak between the plate at the back and the bell/oil tank.

[upnorthelan]

This is sort of a separate question, but I spoke with Primus and Pegasus about a replacement for the clutch tube o ring. Brad recommended rope seal, the same as the perimeter of the adaptor plate. Since my car has holes drilled between the catch can and the oil tank and the tube is submerged I’d prefer an O-ring. I found one thru my local parts store, but was curious if anyone had a specific oring they’ve used and recommend before I put mine in? Mine’s 3.5” od, 3.25” id, .125” diameter. It fits pretty well, but seems a little larger than the one that came out. I’m concerned it won’t compress enough.

[bassracer]

I'm taking a closer look at this again this winter. 2 years ago I used a rope for the plate perimeter but an O-ring for the tube section since it can be completely surrounded by oil. The O-ring i used was a #152 round profile. I also use black rtv on the bellhousing side of the plate - so one or the other is technically redundant. Overall paranoid of having a leak at hard-to-reach location once everything is together.

This last season I noticed a slow drip coming from below the bellhousing. I recently pulled the gearbox off and and noticed oil in the tube again. I assume this is from back plate so will be looking very closely at the o-ring to determine if a larger profile or possibly a square-profile will be better.

[DaveW]

Use a Viton o-ring - they don't take a set as easily as some others, and are impervious to everything except brake fluid.