Brake specialists?
Discussion
I need some help with the brake set up on my car.
Brake performance is poor and after playing around with different master cylinder cylinders, I think it is time an expert to a look at the pedal box and gave a thorough assessment.
Anyone recommend someone who is a dab hand at bespoke brake systems?
Ideally, someone situated between Manchester and the South.
Cheers
Brake performance is poor and after playing around with different master cylinder cylinders, I think it is time an expert to a look at the pedal box and gave a thorough assessment.
Anyone recommend someone who is a dab hand at bespoke brake systems?
Ideally, someone situated between Manchester and the South.
Cheers
Hi Guys, thanks for the replies.
The car (although largely irrelevant because there is nothing original left;)) is an old 'un, a Rochdale Olympic.
The car has undergone a full rebuild in someone else's hands, I'm now trying to get it right.
It has all round disc brakes from a BMW E30.
The brake master cylinder (bore size 11/13") comes from a Metro of all things.
Braided hoses.
Mintex pads.
Bespoke pedal box that is top mounted to the drivers footwell.
The problem on the road is too little stopping power basically. Just impossible to stop safely whatever pressure is applied. No chance of locking up put it that way.
A larger master cylinder has now been fitted, and although an improvement, no way strong enough still.
The pedal design is strange, which makes me unsure of the ratio itself.
The car (although largely irrelevant because there is nothing original left;)) is an old 'un, a Rochdale Olympic.
The car has undergone a full rebuild in someone else's hands, I'm now trying to get it right.
It has all round disc brakes from a BMW E30.
The brake master cylinder (bore size 11/13") comes from a Metro of all things.
Braided hoses.
Mintex pads.
Bespoke pedal box that is top mounted to the drivers footwell.
The problem on the road is too little stopping power basically. Just impossible to stop safely whatever pressure is applied. No chance of locking up put it that way.
A larger master cylinder has now been fitted, and although an improvement, no way strong enough still.
The pedal design is strange, which makes me unsure of the ratio itself.
Paul Drawmer said:
You will have to push bloody hard without a servo.
A smaller master cylinder (diameter) will make it easier.
Make sure the pads are high friction type - I doubt if you need harder type pads.
Sorry, didn't bother mentioning the servo, which is a Metro servo again. A smaller master cylinder (diameter) will make it easier.
Make sure the pads are high friction type - I doubt if you need harder type pads.
The primary issue isn't the amount of pressure I have to place on the pedal, although that is not right. The bigger issue is that whatever pressure I exert on the pedal, the force isn't saitisfactory.
So, anyway, my original question - anyone recommend somewhere who will be able to diagnose and fix?
not a brake specialist but kit experts who I know very well and recommend.
http://www.southwaysautomotive.co.uk
http://www.southwaysautomotive.co.uk
Sounds like either your master cylinder bore is too big, or your pedal ratio isnt big enough, or your servo isn't working. It should stop on a sixpence with those brakes and a servo.
Manchester to the south is a big area; Care to narrow it down a bit? My workshop is in Stalybridge (east of Manchester) and I'll happily give you an oppinion but we're a general car garage rather than a kit specialist. Chester Sports Cars have a decent rep' over near Chester (amazingly)and specialise in kits. There's loads of places between here and Dover though.
Manchester to the south is a big area; Care to narrow it down a bit? My workshop is in Stalybridge (east of Manchester) and I'll happily give you an oppinion but we're a general car garage rather than a kit specialist. Chester Sports Cars have a decent rep' over near Chester (amazingly)and specialise in kits. There's loads of places between here and Dover though.
godspeed brakes http://www.godspeedbrakes.co.uk/ In South Wales though, so not quite where you were after.
alolympic said:
...The primary issue isn't the amount of pressure I have to place on the pedal, although that is not right.
The bigger issue is that whatever pressure I exert on the pedal, the force isn't saitisfactory.
Isn't it all the same thing?The bigger issue is that whatever pressure I exert on the pedal, the force isn't saitisfactory.
alolympic said:
So, anyway, my original question - anyone recommend somewhere who will be able to diagnose and fix?
Only trying to help The set up you have sounds similar to a GTM Libra.
Although even with standard Metro discs on the front and MGF rears they will lock up you have to press the pedal quite hard. This was mainly down to the low pedal ratio 3-4:1.
Is it possible for you to measure it? 6:1 is more usual and should give better pedal feel too.
Although even with standard Metro discs on the front and MGF rears they will lock up you have to press the pedal quite hard. This was mainly down to the low pedal ratio 3-4:1.
Is it possible for you to measure it? 6:1 is more usual and should give better pedal feel too.
Hi Guys,
Thanks for the info. I'll try Southways first I think.
Umm, no not really. The force required and the force generated I see as 2 different factors.
If the car stopped as required - just needing a lot of pressure, I could live with it.
However, irrespective of how much pedal pressure I exert now, the set up is not able to stop the car quick enough - even if I stamp on them. This makes me think, the system isn't able to move enough fluid at the correct psi.
Sorry, didn't appear to be ungrateful, I just know that I can't fix myself, and will need a specialist to look at them in person.
Thanks anyway.
Thanks for the info. I'll try Southways first I think.
Paul Drawmer said:
alolympic said:
...The primary issue isn't the amount of pressure I have to place on the pedal, although that is not right.
The bigger issue is that whatever pressure I exert on the pedal, the force isn't saitisfactory.
Isn't it all the same thing?The bigger issue is that whatever pressure I exert on the pedal, the force isn't saitisfactory.
Umm, no not really. The force required and the force generated I see as 2 different factors.
If the car stopped as required - just needing a lot of pressure, I could live with it.
However, irrespective of how much pedal pressure I exert now, the set up is not able to stop the car quick enough - even if I stamp on them. This makes me think, the system isn't able to move enough fluid at the correct psi.
alolympic said:
So, anyway, my original question - anyone recommend somewhere who will be able to diagnose and fix?
Only trying to help Thanks anyway.
the original 21mm master cylinder is not too big for that brake set-up with discs all around. should be perfect.
i use such a bore size for escort mk2 front brake calipers and rear disc drums (escort mk2).
pedal is very hard but is still acceptable, although when you come from a "normal" car its definately too hard.
also, as i understood yours is servo assisted, so the brake pedal should feel rather spongy than hard?
does the servo work...that would be the main question here, also what makes me concern:
you can fit the best brake parts in your car but those will not make sense when the ratio, the pedal bix gives you , is way out.
to-do list:
1. ratio
2. check servo
i use such a bore size for escort mk2 front brake calipers and rear disc drums (escort mk2).
pedal is very hard but is still acceptable, although when you come from a "normal" car its definately too hard.
also, as i understood yours is servo assisted, so the brake pedal should feel rather spongy than hard?
does the servo work...that would be the main question here, also what makes me concern:
you can fit the best brake parts in your car but those will not make sense when the ratio, the pedal bix gives you , is way out.
to-do list:
1. ratio
2. check servo
Edited by Comadis on Tuesday 25th October 18:51
I am still trying to get to the bottom of this problem with Southways help.
Turns out the servo isn't really getting any vacuum through the inlet manifold, probably because the engine is running a hot cam.
So, I can pay for an electric vacuum pump but have been warned that this may just be about making the best of a mis matched set up.
I am now thinking this all seems a bit silly if I'm not getting the right sort of brake line pressure, so have I want to test that before I spend any more money.
Rally Design sell a Wilwood pressure gauge, which I presume will do the job?
http://www.rallydesign.co.uk/product_info.php?cPat...
Can anyone tell me what else I will need to test?
Cheers
Turns out the servo isn't really getting any vacuum through the inlet manifold, probably because the engine is running a hot cam.
So, I can pay for an electric vacuum pump but have been warned that this may just be about making the best of a mis matched set up.
I am now thinking this all seems a bit silly if I'm not getting the right sort of brake line pressure, so have I want to test that before I spend any more money.
Rally Design sell a Wilwood pressure gauge, which I presume will do the job?
http://www.rallydesign.co.uk/product_info.php?cPat...
Can anyone tell me what else I will need to test?
Cheers
I used to own a Lotus Elan which I believe weighs almost the same as an Olympic.
I had problems with the servo and disconnected it, and it would still easily lock the wheels and stopped so well I never replaced the servo.
Is it possible to bypass the servo and see what happens?
Assuming the master cyclinder and all four callipers are free and working, you aren't losing brake fluid and none of the brake pipes has been crushed.
Then it must be a case of pads that are much to hard (designed for a much heavier car with a powerful servo) or the pedal leverage that must be at fault.
Good luck
I had problems with the servo and disconnected it, and it would still easily lock the wheels and stopped so well I never replaced the servo.
Is it possible to bypass the servo and see what happens?
Assuming the master cyclinder and all four callipers are free and working, you aren't losing brake fluid and none of the brake pipes has been crushed.
Then it must be a case of pads that are much to hard (designed for a much heavier car with a powerful servo) or the pedal leverage that must be at fault.
Good luck
When you say no amount of pressure will lock the wheels, what is the pedal travel like? I'm guessing virtually no travel.
Single MC so I'm assuming it's using a proportioning valve of some sort?
If so is perhaps junking the servo/prop valve setup and swapping in a twin MC/bias bar setup a viable option?
Single MC so I'm assuming it's using a proportioning valve of some sort?
If so is perhaps junking the servo/prop valve setup and swapping in a twin MC/bias bar setup a viable option?
Edited by Kozy on Thursday 8th December 15:24
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