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Triumph Repair/TR 6 Master Cylinder Replacement


QUESTION: Hi Howard:

This is a follow up to the thread started on 11/23.  I've replaced the brake master cylinder on my 76 TR6 and I'm bleeding the brakes a outlined in one of your previous posts on this subject.  Right rear wheel went fine but on the left rear, it appears a previous owner has jammed a metric bleed valve into the wheel and it is seized completely.  None of my wenches fit the valve and I can't get any movement out of it with moderate pressure using a crescent wrench.  Is there a workaround for this problem?

Even though I've only bled the one wheel, I can pump up good pressure on the brake pedal and no softness develops when I hold it down for a time.

Look forward to your suggestions.

John Kemp

ANSWER: Hi John,

As long as the peddle is not soft then there is not much if any air in the system. Air in the system compresses and that is what makes the peddle soft. So as long as the bad valve is not leaking, you should be able to ignor the problem for now.

Sooner or later you will need to correct the messed up bleeder valve. If this was brought to me in a shop I would advise to just replace the wheel cylinder or wait until some more brake work warrants doing all the brakes and replace it then.

Attempts to remove the crossed threads of the bleeder valve could do more damage and the time would cost more then a new wheel cylinder. If it were an expensive caliper on the front then it might be worth spending the time and effort to repair it.


---------- FOLLOW-UP ----------

QUESTION: Hi Howard:

Thanks for the advice.  I didn't see any sign of leaking around the valve so I'll follow your suggestion and just leave that wheel.  I plan to finish up on the front brakes tomorrow and test things out.  Hopefully no further surprises.



ANSWER: Let me know.


---------- FOLLOW-UP ----------

QUESTION: Well Howard, we have brakes.  Nice firm pedal and a short test drive was normal.  However I noticed something else during the brake bleed.  The ball joint boot (Moss part# 680-760)on the left front wheel is badly deteriorated.  The front side is torn and the boot appears to be squeezing out the back.  Just wondering... a) how critical this repair is and b) how difficult the repair is?  From the exploded diagram it appears to involve just the removal of the lock nut and washer to replace the boot.  Is this correct or am I missing something?



Hi John,

The boot on the upper ball joint can be changed by removing the large nut and then you will need a balljoint tool to remove the stud because it has a tapered shaft. There are two types of balljoint tools. One is a large wedge shaped fork and the other looks like a small clamp. Neither tool is very expensive and can be used to remove tie rod ends also. Most auto parts stores sell one or both types. Some mechanics like the clamp type because the fork often damages the boot when sometimes it is necessary to remove a balljoint for other work and the clamp type does not damage the boot.


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Howard M. Fitzcharles III


Triumph TR-4 up & Spitfire, and Engine theory


Dealership line mechanic on MG, Triumph, Jaguar for 15 years, Instructor in commercial mechanics school 2 yr. Product information manager for piston and valve manufacture, Instructor & hotline answer man for import car parts importer 15 yrs.

Associate member SAE EAA member

Import Car magazine

ASE Master Auto with L-1 certification up to 2000

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