TVR Scott
TVR Scott GRM+ Memberand SuperDork
9/28/23 7:58 p.m.

I'm doing some rebuilding on the hydraulics for my TVR, and I have questions.

Here are the objects of interest:

Is there a good guide on how to do this properly?  Video or written - either would be fine.

The brake reservoir is yellowed but I don't see any cracks and it doesn't seem brittle.  What's the criteria for clean-up vs. replace?  Moss has new ones, but I know there's always concern about quality on new parts.

Moss also has a gasket and o-ring kit with a new tipping valve.  Quality stuff, or is there a better place out there?  Pegasus has Girling stuff, and I trust them.

Anything special in the refinishing process?  I was going to plug the holes on the brake cylinder, sandblast, and then paint.  Caliper paint?  The clutch cylinder is aluminum, so I was going to give it a good scotchbrite treatment and call it done. 

Ball-hone both?  Or use the three-arm doohickey?  What's the criteria for too warn to rebuild?

What am I missing?

TurnerX19 UberDork
9/28/23 8:14 p.m.

The clutch is easy, but new is cheap, and refinishing it removes too much, so no pitting, period. Easy simple if the bore is good. The brake is problematic. There is a snap ring about 1/2 way down the bore, between pistons. I gave up trying to disassemble without scratching the outer bore about 40 years ago. The rebuild kits are still around, but good luck.

Carl Heideman
Carl Heideman
9/28/23 8:39 p.m.

TurnerX19 has said it well. We used to rebuild them at Eclectic, but the new ones are good and the easy button. 

When we did rebuild them, we never honed an aluminum clutch MC as they are anodized and the honing would remove that and make them porous. Then they'd come back in about 3 months. So if they aren't pitted, just put new seals in and you're done. If they are pitted, get a new one.

Regarding the brake MC, we've made special tools to get the snap ring out and also hold the pistons to properly disassemble things, but even then the outer bore gets scratched if you're not super careful. We used to get the bodies replated rather than paint them.

There are low quality parts out there, but we've been happy with new brake and clutch hydraulics.

Oh, to answer the yellowed reservoir, if it isn't cracked, just clean it with carb or brake cleaner and it will be fine. But the new ones are fine, too, and not yellowed.

JoeTR6 SuperDork
9/28/23 9:14 p.m.

7 years ago, I bought a Raybestos master cylinder for the TR6 for reasonable money.  Now, it's $482 from the one place that claims to have it.  It replaced a Lucas/TRW cylinder that just wouldn't bleed properly (sucking in air from somewhere).  At least those are cheap.  My experience with rebuilds is not very good.

I have an original 0.70 clutch cylinder sleeved with brass that you can try to rebuild.  The outlet needs some machining to clean up the sealing surface.  Also, the end of the bore has some roughness that lets fluid back into the reservoir.  Maybe you can save it, and the rebuild kits are fairly cheap. 

TVR Scott
TVR Scott GRM+ Memberand SuperDork
9/29/23 9:45 a.m.

Okay, good to know.  Sometimes just buying new is the right answer!  I'm glad to hear the new hydraulics are pretty good quality.

I'll pull apart the clutch cylinder and see what it looks like.  No pitting, and I'll order a rebuild kit.

Joe, did you have that one sleeved with the brass or did it come that way?  I saw some references online to doing this.  I might take you up on the rebuild offer.  Could be a fun project to try.


JoeTR6 SuperDork
9/29/23 10:15 a.m.
TVR Scott said:

Joe, did you have that one sleeved with the brass or did it come that way?  I saw some references online to doing this.  I might take you up on the rebuild offer.  Could be a fun project to try.

The brass sleeve was done by White Post Restorations years ago.  It didn't leak from the bore, but I couldn't get the outlet to completely seal and lacked the machinery/knowledge to fix it.  As a bonus, the outside is already cleaned up and clear coated.  What I'm not sure about is whether the current TRW rebuild kits will fit an original Girling cylinder.

TVR Scott
TVR Scott GRM+ Memberand SuperDork
9/29/23 3:27 p.m.

I think I just found my answer on the clutch cylinder:

Silly me for thinking anything original from this car could be reused.

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