View Full Version : TR6 TR6, Clutch Mast Cylinder disassembly

02-24-2005, 09:54 PM
I'm trying to get the piston out of the clutch master cylinder so I can install new seals etc. Tried blowing compressed air into the unit, no joy. I can push the piston back into the cylinder, and the spring returns it, but it stops like it is hitting a ridge. Any ideas? Bentley says blow air into it... /ubbthreads/images/graemlins/hammer.gif

02-25-2005, 12:27 AM
It's been several years since I've pulled the clutch MS so I'm relying on a sketchy memory - have you removed the lock ring?

02-25-2005, 12:30 AM
I'm assuming you have the snap-ring out and the metal washer is loose(it should have come out with the actuator rod) If this is so then what you're agenst is a ring of corrosion that formed behind that plate.
If you can push the piston in and it will return then I would say to push it in and spray it with WD40. Then work it in and let it spring out and see if it starts coming out further with every plunge.
If it sticks when you push it in then Spray it with the WD40 and bang it (open end down) on a wooden surface to get the plunger to return. Keep pushing it in and banging it(don't kill it, you don't want to damage the cylinder) until it works freely then refer to the first step.
This said, if the plunger is that stuck, then it's likley that there is enough corrosion in the bore that it's pitted and beyond being able to save.
Good luck Guv'na

02-25-2005, 02:17 AM

Someone else here gave me a suggestion that worked really well with my clutch slave cylinder, should work on any of the hydraulic masters or slaves on the car. Use a grease gun.

First, fit a zerk where the hose usually goes. Leave the bleeder screw tight and plug any other holes (a bolt with the right thread will work temporarily). You may need to take the cylinder with you to an auto parts store to find the right size zerk. My TR4 has fittings throughout that take 3/8" zerks. Larger zerks like this are often tapered, sort of a fine pipe thread I think, so won't screw very far into the straight threaded fitting off the cylinder. Still, it may be enough to temporarily fit one and do the job.

If however the grease comes back out around the threads of the fitting and the piston still doesn't pop out, consider using a die to cut and straighten the threads on the zerk so that it fits the cylinder better. In my case, a standard 3/8" NF die worked. I think some later TR6 and/or replacement parts might have metric threaded fittings in some or all of the hydraulics.

I agree that it's possible the cylinder is damaged by corrosion, if it's so badly stuck. If so, you have a choice to replace it or to have it sleeved by someone like Apple Hydraulics.

Here's another tip, whatever you do to get the master cylinder back into usable condition, use a proper lubricant when reassembling it. It's possible to just use brake fluid for this purpose if a car is immediately being put back on the road.

But, there are better greases and oils made for this sort of reassembly that should be used instead, most especially if the car will be sitting a while during restoration. If brake fluid is used and/or the rebuilt system is filled with brake fluid now, and the car sits for a few months, new corrosion will likely set in and you could well find yourself doing the job all over again in 6 months or a year.

Look at auto parts stores for greases and oils that are compatible with brake fluid, made specifically for this purpose. I know Raybestos makes an oil, and Lucas sometimes supplies packets of grease in rebuild kits. Use just a little on the seals and all rubber parts and wipe a very light coating on all metal surfaces inside and out, to keep corrosion away until the car is ready to use.

When it's time to take it on the road, fill the hydraulic systems with fresh brake fluid, bleed them and you'll be ready to go.



02-25-2005, 02:20 AM
Thanks to both of you for your replys. The snap ring, washer and actuater rod have been removed. I've just been struggling with getting the piston to come out. I will continue with the WD-40 treatment. I just wanted to make sure that I was not missing something important or something I could damage without realizing it.

Looks like I just need to be a bit patient, enjoy a pint /ubbthreads/images/graemlins/thirsty.gif and continue to work it /ubbthreads/images/graemlins/hammer.gif.

Thanks again.

02-25-2005, 02:28 AM
Thanks Alan.

The problem with the Clutch Master cylinder is that the fluid reservoir is so large you would require a substantial amount of grease to fill it in order to exert the pressure on the piston. When I applied compressed air to where the zerk fitting would go, I blew the cap off the fluid reservoir.
Thank you again for the input. I know I will be able to put it to good use in the future.

02-25-2005, 09:22 AM
The grease gun Idea works well. I've done that before, but like Jimmy G said, it dosen't work so well on the later style cylinder with an integral reservoir. The TR2-4 used a remotely mounted reservoir so it worked like a charm.Just like he said,Zerk fitting in one hole, bolt in the other, viola! Starting with the TR4A they used a cylinder with a reservoir cast right on the cylinder. There's no good way to block off the hole in the bottom without some creative engineering.
Definatly a good tip to have in your pocket for future refrence though! Slave cyl,wheel cyl, etc...
how about mounting the cylinder in a vice that will hold the reservoir cap in place? /ubbthreads/images/graemlins/grin.gif

02-25-2005, 05:47 PM
I used air pressure, but down at my buddy's shop (professional huge compressor.)

Try taking it down to a local mechanic shop and see if someone can quickly blow it out with their industrial compressor.

02-25-2005, 07:40 PM
You ain't never gonna get it out...............untill you remove the tipping valve, under the resvouir there is a big allen screw, remove that, pull out the valve, then presto chango, parts come flying out.

02-25-2005, 07:46 PM
By the way, that grease trick is mine, I invented it, right after Rock n Roll and just before the innernet

02-25-2005, 08:29 PM
I just had my clutch MC apart with the same problem.
I pushed the piston in and while holding it there LIGHTLY removed the very small ridge with a small dremel sanding cylinder, you could also likely do it with sandpaper on your finger.
Then bang the MC upside down on something reasonalbly solid and it pops out.
Good luck.

02-26-2005, 02:25 AM
Thanks to all. Boxorocks, reading your last post made me go down to the garage to look at the Master Cylindar to see if there was an allen screw somwhere I had missed. There was not. But on the way back upstairs I banged the open end of the cylindar on the carpeted staircase several times and the piston came out a little bit. I went back to the garage and gave it another burst of air and it popped right out. Yippee...Something to do tomarrow. Rebuild the thing and get it back on the car. /ubbthreads/images/graemlins/driving.gif

02-26-2005, 04:34 PM
You ain't never gonna get it out...............untill you remove the tipping valve, under the resvouir there is a big allen screw, remove that, pull out the valve, then presto chango, parts come flying out.

[/ QUOTE ]

That's the Brake master, he's on the Clutch master. But you're right.(1/2" allen)

02-26-2005, 05:59 PM
AAA...duh. never any good at reading directions