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MG MG Y Type - MGYA Brake Function

Hi,
I am trying to establish how bad MGYA brakes were originally.

I have just driven my rebuilt YA for the first time in 24 years...then I only drove it 30 miles before taking it off the road.

I know that the YA system was poor but I was surprised how poor they were yesterday.

This is a totally rebuilt system with new cylinders, pipes and shoes and rebuilt master cylinder.

Does anyone have a UK MOT Brake Efficiency document which now comes with the MOT Certificate.....if so can you give me the various brakeforce figures given.

Thanks

Rob
Rob King

Hi Rob

Actually original Y brakes, when a) properly adjusted on b) rounded and trued wheel drums with c) a properly adjusted stroke piston into the master cylinder and d) an air free, hydraulic system using DOT 4 and e) no hydroscopic absorption of water into the fluid are extremely effective and I have never had a problem stopping on them.

By way of a story, a Y owner here brought me his car after he bought it complaining it had 'no get up and go'. I fixed that for him with a proper tune up and he brought it back saying 'Wonderful now, it goes great but it doesnt stop for a damn!'. So I did all of the above, replaced his original hoses and worn out wheel cylinders with the correct parts, new springs, shoes etc adjusted them, had his drums rounded etc. and sent his master cylinder over to C&C Parts for overhaul, refitted and readjusted it all and returned the car to him. Now he tells me he thoroughly enjoys driving with confidence at sensible speeds for the road conditions knowing that he can stop in a controlled way.

My guess is that the brake pedal and the piston are not adjusted properly - see the WSM for details as to how to do this. Once you do it you will be surprised I hope! Also have someone check the ovalling/ out of roundness on your drums, and that the shoes are correctly adjusted.

As to brake force for your UK MOT - the importance is evenness in all 4 corners. I used to use stalling out as a rule of thumb. Then I would take it down to the local village MOT station and work on them there with the guys.

Does that help you any?

Paul
Paul Barrow

Rob: I tend to agree with Paul, and would add that you need to give the new linings and drums some time to bed in, and to allow for the fact that in an age when we're so used to servo-ed brakes and light pressure inputs to steering and other controls, you will have to get used to simply pushing harder with your right foot!

My MOT inspector was always very complimentary about the braking forces a 75-year-old brake design could generate, and the car can certainly stop very effectively when called upon to do so. So I'd follow Paul's advice, check everything carefully, and then go out and drive! Good luck!
Tim Griggs

Hi Rob,
Good to see you have now got the Y on the road. I understand your problem as I experienced similar problems when I put my newly restored YA back on the road.

The problem I believe is the amount of contact your new shoes have with the drum, single leading brake shoes take quite a while to bed in. Only the leading edge contacts the drum initially, the more you use them more shoes comes in contact as they wear. I have now done 1700 miles and adjusted them up 3 times. They have now improved however I still hope for a little better performance as I get more miles on her and they bed in further.. The last time I looked just over half of the brake shoes was showing wear from drum contact.This winter I am going to have another look and give them some further adjustments.

cheers chris
P'S are you going on the spring run weekend this year.
C A Pick

Hi Rob

I agree with Paul, Chris & Tim. When I take my YT for the 'not compulsory MoT', I always request the garage to test it on the rolling road. They are always surprised at the good readings given, which would also be a pass for modern vehicles. Obviously, without a servo, we have to push hard on the brake pedal.

I also had to have my front drums rounded at an engineering works before the brakes worked well.

Good luck with your brakes

Anil
bles1

I have owned a Scott 600cc twin since the 1950s which had front brakes which required a very strong grip to apply. More recently I restored the machine and on the advice of the Scott club advised me that the brakes were probably fitted with a high temperature racing linings, which was probably so because it had been used for club racing in the early 50s by the previous owner, it certainly could top the ton. On fitting new linings the twin front brakes became more sensitive and effective, which is fine for my sort of speed. The upshot is that it could be that the brake lining compound may be unsuitable for your car. I have noticed that various owners seem to get differing results from similar types of car.

ps as a foot note ,if you have the master cylinder re lined ensure that the bleed hole is drilled through.

Bryan

B Mellem

Hi Guys,

Thanks again for the advice.....I think the issue was 'bedding in' as you said Chris.

Only done 65 miles so far but the brakes seem to improve by the mile.

Just had a full MOT today and passed with flying colours 78% efficiency on the brakes!

Rob King

This thread was discussed between 04/12/2014 and 23/12/2014

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