Long Brake pedal travel TA/TC &TC21/100

Does anyone have a solution to the above original feature on these cars? I have just about got used to it on a friends TC21/100,which I look after, but at its recent MoT  there was some excitement when my usual sympathetic tester thought he wasn't going to stop as the pedal headed for the toe board. Needless to say the car passed the official test no problem but collected the following advisory " Little reserve travel but advised by owner this  feature of this model still servisible" I believe the problem relates to the relatively small bore of the master cylinder and the large diameter of the 6 wheel cylinders and the big bore brake lines,basically lots of fluid needs to be displaced before anything happens hence the long travel at the pedal.I have played around the the adjustable actuating rod which helps in the short term but you end up with the brakes binding or the brake lights on all the time.The brakes do not need bleeding and the shoes are adjusted correctly.My TA  with the same m/cylinder  has TE discs at the front and a servo does not have this issue. Any ideas welcome. Posted by Peter Martin 23/04/2013 18:11:54

Peter,  Other things being equal, namely that the master cylinder in particular is not at fault and that you are not losing fluid in the circuit, I feel that you may need to go back to your two "givens", namely the brake fluid and the shoe adjustment and reappraise these. I assume that your car is fitted with micram adjusters and that they have been adjusted right up then backed off a notch. This is easy to achieve and thus eliminates one variable. That really only leaves the brake fluid. To that end there must still be air in the system that is being compressed. From experience it is at times difficult to expel all the air as there is only one bleed point per front wheel yet there are two cylinders. I have found that air is still trapped and it takes much perseverance to shift it. The rear cylinders are much easier to bleed.  All in all I would recommend that you bleed the system again.   Regards  Richard Posted by RichardWallach 23/04/2013 23:21:07

re bleeding - you will get better results if you can close the brake cylinders as much as possible (ie the position with unworn drums and new shoes) during the bleeding process. Otherwise it is very difficult to expel the air already in the main bore of each cylinder. Also, I recommend that final bleeding is done with two people - the use of vacuum pump on each bleed point can work well, but the pressured reservoir approach is only good for initial bleeding of most of the problems (in my opinion)  good luck Posted by DaveT 24/04/2013 11:37:25

Having been used to the servo assisted disc brake setup on the later 3 litre cars I was initially disappointed with the general feel of my TC21/100 brakes. I had renewed all the hydraulicsand the brakeshoes looked to have plenty of life in them, I got the MOT passed okay but in the end I fitted a brand new set of 'shoes from Chris Prince and the car was transformed, the brakes are nice and progessive with plenty of bite when you need it. I agree that the front brakes can be difficult to bleed completely, I have left them on a 'slow drip' for an hour or two which seemed to do the trick.  Andrew Posted by tf1695 24/04/2013 15:20:58

Thanks to all for your suggestions, I plan to bleed the brakes within the next 2 weeks and report back. For the record the car has virtually new shoes (CP),there is no fluid weeping at the master or wheel cylinders ,the fluid is recent, the adjustors are done up  to spec, the hoses look good but may be inflating under pressure.The pedal is hard when it gets there and it does not feel like there is air present which in my experience usually gives a spongey feel and this can usually be made to go away by pumping the pedal.Maybe I will have to live with what the period road testers commented on.eg "As with the previous model (TA21)the brakes gave rise to some concern at first due to a long pedal travel....proved well up to their job..... to be classed as a peculiarity rather than a fault " said in Motor Road Test of a TC21/100 in 1954.There are similar comments from other testers. Posted by Peter Martin 28/04/2013 12:54:13

Heve you checked the free play at the brake pedal ? The handbook says there should be about 1/2'' free movement at the pedal pad. This is the only free pedal travel there is on my TC21/100, then I 'have brakes'.  Good Luck Andrew Posted by tf1695 28/04/2013 15:39:03

Thanks Andrew I have played around with the length of the actuating rod and understand the huge effect incorrect adjustment has on pedal travel. I plan to reduce the free movement to zero to see what happens.I know if I   put on a little bit of +ve. pressure the brakes feel "proper" but then  other issues  appear because the system can't recover.(Brake lights on permantly followed by binding) Cheers Peter Posted by Peter Martin 29/04/2013 09:57:43

Think finally got it fixed.A combination of the following;Shoe adjustment, 2 micram adjusters needed + 1click,Bleeding, I wheel cylinder,the NSF had a tiny amount of air,Pedal free movement, reduced to give minimal clearance on actuating rod ,about 20thou.as per later disc braked cars, this gives about 1/8" at the pedal.Car  feels transformed,maybe the road test cars just needed their brakes adjusted. Thanks again to all for encouragement. Posted by Peter Martin 06/05/2013 13:45:52