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TR2/3/3A Breaks Locking up after a short drive

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Born_Loser

Born_Loser

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Got a new problem. Back story - had a leaking master cylinder. Ordered a rebuild kit from Moss (Gerling system - so I did both clutch and break master cylinder). While I was at it, I replaced the fluid reservoir . Since I had it apart, I rebuilt the peddle assembly - it was a mess, with the shaft seized to the break peddle - and the end bolts removed. The peddles are both free, and have a fraction of the lateral play they had before. I bled both systems, and noticed a bit of small black pieces in the clear bleed tube on one of the rear breaks. So, I ordered stainless steel break hoses, and replaced all 3. Flushed all the fluid, and the bleeds where clear. Clutch works like a champ. The breaks have very little travel, and when I stop for more than a minute after a short drive, all 4 breaks are locked. If I stop at a stop sign, they drag for a second and then free. But, if I park, they will be stuck in a minute or 2. I honed both masters, and the seals looked identical. Suggestions on how to diagnose the cause?
 
I have not adjusted the calipers, I thought they were self adjusting (my service manual states that). The fronts do bind-drag a touch -they always have (I have had the car for 13 years). I can turn them with or without the tire mounted, so I didn't think it was a big deal.

Thanks for the welcome, I have enjoyed the BCF occasionally for a few years now, but, never needed advice. And I'm no expert, so I haven't offered any either!
 
How old are the brake rubber hoses. They are very bad to swell up on the inside. They allow brake fluid to go thru from foot pressure but lock the brakes up for a while until the fluid can leak back thru the hoses.

Marv
 
check the "TEE" near the right front wheel. I had the same problem many years ago. There was sludge in the fitting. Cleaned it out and no more dragging. Just a suggestion.
 
Thanks, I guess I will be taking apart the "T". That seams logical. I did just replace all the hoses, no swell from those, stainless steel.
 
I think that "TEE" is the residual pressure valve. If you do a little searching on this forum you should find a lot of information and opinions about it. I gutted mine because I was having trouble getting all the air out of the system. But I think if it were clogged up, it might cause the sticky issue you have.
 
Problem solved! Thanks for the input. I was going to take the "TEE apart, and I started with the main line from the master. I had sealed the reservoir - trying to create a bit of a pressure lock, to prevent the pipe from draining (and thus filling with air). When I loosened the pipe, it seeped - a lot. There was clearly pressure on the main line from the master. So, drove it a pit, to build the pressure back up, and loosened the line at the master - pressure there as well. So, the master was the problem. I was 100% sure I put the seals together correctly inside the master. But, there was one thing different. The Moss kit came with 3 seals. The 2 that were inside the master, and a 3rd. My book shows the 3rd sitting outside the piston, between the piston and the washer on the peddle linkage. When I disassemble my leaking master, it did not have that 3rd seal. The seal seamed like a good idea, so I used it (on both clutch and brake). That was the problem. I removed it, and the breaks are 100% free - no drag (the drag I had originally was probably from the hoses that were a bit soft). Just took it for a series of progressively longer test drives (with my 7/16 line wrench in the glove box), no problems at all. I left that seal in the clutch - its not riding at all. I don't know why it was causing the piston to not return 100% sometimes, but, it wasn't!
 
Is that "3rd seal" you refer to pretty much an o-ring on the piston? If so, that was pretty much dropped sometime during the Kennedy administration, and AFAIK it is not necessary to use any sort of seal / o-ring / whatever on a cylinder with that groove in the piston.
 
The "end seal" is what I am talking about. It looks exactly like this one (out of my Service Manual). I am guessing that my masters where replaced with "not exactly" originals at some point. They are marked "Made in Australia". I have rebuilt several of these - they look identical to the ones in both of the Spitfires I once owned - those didn't have the end seal either.

TR3 Master.jpg
 
LOL, well, I am opting for "leave it out"! No grease in the kit. I have 3 books on this car, all 3 show that drawing with the "end seal", yet, not one of them makes mention of it in the assembly or dis-assembly. I am just happy its solved, but, I blew a mid 70's day, not a cloud in the sky figuring it out.
 
Hi Born_Loser,

"Welcome" back to the BCF.

Now your a "Born_Winner"!!

Happy Motoring,

Russ
 
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