Brake Balance

[paul richards]

My front brakes are less effective than they were. Since the car was new, the brakes have always required a firm push, but I always put this down to the lack of servo, which I am used to on the tin top. In the last few months they appear to have become less effective and I worry that under hard braking I'm going to get rear lock up which will make the car unstable. I examined the front brakes and calipers appear to be free and I replaced the pads (Mintex MGB533 - standard fitment), thinking that they were glazed.

Little or no improvement. I plan to bleed the brakes, but suspect this will have little effect as the pedal is quite firm and not spongy.

What is the solution other than uprating the front brakes (reluctant to spend £500 or so). I'm sure even the standard brakes should be better than this, it's a very light car after all.

Any suggestions appreciated.

 

Paul Richards

Joint AO - L.A.D.S. (Lancashire and District Sevens)

 

Edited by - Paul Richards on 14 Nov 2003 13:27:16

 

Edited by - Paul Richards on 14 Nov 2003 13:31:24

[paul richards]

Thanks for all your replies - I'm underwhelmed.

Someone has suggested Mintex 1144 pads for the front. Any comments?

 

Paul Richards

Joint AO - L.A.D.S. (Lancashire and District Sevens)

[Mr Locust]

I have used EBC greenstuff in std spit iv calipers (when I had the the Locust) with good results.

 

Good 'feel' and 'bite'. As with anything like this braking charachteristics are very subjective.

 

They did tend to get the coaldust appearance on the wheels pretty quickly but I put that down to them being soft enough to do the job properly.

 

Ian

 

Green and Silver Roadsport 😬

[JAG]

Paul,

 

have you checked that all the brakes are free of corrosion and all the pads are moving and the rear brake housings are sliding properley?

 

Take the pads out of one of the front brakes and get a friend to VERY GENTLY press the brake pedal. Check that all the pistons in each front caliper move freely, that the rubber boots/excluders around the pistons are in good condition (not ripped etc...). With the pistons protruding a little carefully remove the rubber boot/excluder and check that the front pistons are not corroded. Repeat for the other front caliper.

 

Do the same with the rear calipers.

 

If you have a copper/steel brake pipe fitted directly to the rear calipers then replace this with a flexible hose as the steel/copper pipes are rigid enough to stop the rear caliper sliding (I don't understand why Caterham continue to do this but they do!) - this is just a good idea and probably not related to your original problem.

 

See if you find anything like this - if you are still having problems feel free to email me off list.

 

Last remark; If kept in good working order there is absolutely no reason why you should need to upgrade the front calipers.

 

 

 

 

Justin

 

Only two things are infinite, the universe and human stupidity, and I'm not sure about the former.

[Richard Price]

Paul,

I'm running standard rear pads with M1144's in the front, and confirm that they work well.

Running standard, caterham supplied, pads front and rear resulted in too much rear bias with the rears locking before the fronts.

I tried "Green stuff" but I found it most inconsistent.

I swapped to 1144's in the front and now have good performance with the fronts locking consistently just before the rears.

 

There has been talk recently of cutting material away from the rear pads, but I am happy with the way my brakes work!

 

Incidentally, I found that a local "PartCo" was the cheapest supplier. I rang round several places and got a different quote from different PartCo branches, both cheaper than the other quotes I got!

[tiddy1]

Fitting a brake bias valve is quite cheap £80 and will allow you to reduce the rear bias,

 

I found it has made a huge difference, and can be adjusted from the cockpit so you can add more rear bias in the wet

 

Simon

[Jason Plato]

I also run 1144's but with the "big" brakes , the performace is good , but not as good as Pagid pads which I have tried in other cars . Pagids have a much better initial bite bt they cost a lot more .

 

I doubt 1144's will give you any better initial bite than the ones you are using , its just that the 1144's will fade less at high temps .

 

I would go with jag and clean all the brakes and sand the pads down , then retry .

 

Dave

 

 

 

Lotus 7 Club Speed Champion 2003

South Wales Area Organiser

C7 TOP

[julians]

Is it easy to fit a bias valve, what tools arr needed, and whereabout in the braking system does it fit?

 

I have the normal small brakes and my car locks the rears before the fronts, I'm running mintex 1144 on front and halfords chocolate pads on the back.

 

Edited by - julians on 14 Nov 2003 15:43:46

[Chelspeed]

Brake wise it fits in the pipe between the rear connection on the master cylinder and the flexible pipe that feeds the tee piece on the de dion tube.

 

Physically you can fit it anywhere. Some people fit it on the scuttle under the bonnet and take the bonnet off to adjust it. Some people fit it just inside the transmission tunnel with the adjuster knob inside the car so they can adjust it while driving. Certain types of motorsport specify that the driver cannot be able to adjust while sat in the car but it's not something I've ever been criticised at scrutineering so I don't worry.

 

Assuming you have standard caterham solid copper brake pipes you'll need to remove the pipe described above. Bolt the adjuster in somewhere and make up a couple of new brake pipes, one between the master cylinder and the brake limiter inlet and another between the brake limiter outlet and the flexible on the de dion. Bleed the brakes and the jobs done. Normal get out clause follows: If you're not confident working with brake pipes then get someone else who is to assist.

 

Adjust the limiter fully off then drive and stand on the brakes, the rears will lock as normal, increase the limite,r do it again, then repeat until the rears just don't lock.

[SvenDriver]

I've put Mintex in the front and standards in the rear. This for me gives a very good balance for road and track. Before with standards all round the back locked too quickly.

[david nelson]

Puting a balance valve in does not resolve the problem, just hides it. The standard brakes alway did me well in my last 7. I used 1144's at the front and standard at the back.

 

The answer to your question must be: If your bakes used to work, whats wrong now? keep looking till you find it and then fix it.

good luck

[paul richards]

Justin

Thanks for your suggestions. When I examined the calipers I did check all the things you suggest and they are all free. I haven't checked the rear brakes, but I am pretty sure the problem doesn't lie here. I rebuilt all the rear end last year and replaced the rigid brake pipe with Goodridge flexible hose - I've never been too keen on the fixed pipe from the day I built it. The thought of a fixed pipe and the movement required by the caliper seems a bad idea to me.

On reflection, perhaps the improved rear brakes have highlighted the problem?

I thank you for your comment :-

If kept in good working order there is absolutely no reason why you should need to upgrade the front calipers.

I agree.

All

Thanks for all your comments. I plan to try 1144s (or even EBC greenstuff) on the front which seems to have improved things for a number of you. It's interesting to note that I'm not on my own with this problem.

I'm not keen on fitting a brake bias valve, as I agree with the comment that the problem is being masked - All you are doing is reducing the efficiency of the rear brakes to match poor front ones.

I wonder whether a change of disks might be of assistance?

 

 

Paul Richards

Joint AO - L.A.D.S. (Lancashire and District Sevens)

 

Edited by - Paul Richards on 16 Nov 2003 18:11:54

[Paul McKenzie]

Paul,

 

Just a comment or two.

 

Standard Caterham front brakes are good, IMHO, but the pedal gets very flabby after sustained track work, even taking precautions of cooling down lap and obviously no handbrake in the paddock. There is massive heat soak into the brake fluid via the calipers.

 

Caterham upgraded front brakes are, IMHO, awesome and the difference between racing car brakes and fairly reasonable road car brakes. If you don't have your harnesses really tight with the upgraded brakes and a quick driver, I can guarantee you'll be wondering how the bruised shoulders happened the next day. Chalk and cheese AFAIAC.

 

Paul

 

 

[Chelspeed]

I agree that a limiter in the rear brake line is trying to reduce the efficiency of the rear brakes to match the fronts but is that a bad thing?

 

Caterham have chosen the Sierra rear brake caliper for a number of reasons, cheap, easily obtainable, likely to be around for years, handbrake cable provision. The fact that it was designed to stop a 5 seater car full of overweight middle aged people towing a caravan probably was not one of the reasons.

 

The Herald caliper on the front was chosen for similar reasons (except for the handbrake bit...) but approx 20 years earlier when cars were lighter, tyres were crossplys etc etc. As the Caterham is even lighter this is still a good caliper for this application.

 

So the fact that they end up mismatched is not really a surprise. You can't put a valve in to increase the efficiency of the front calipers so you need to put a valve in to reduce the efficiency of the rears. Don't worry about masking a problem, the problem is there, the rears do lock before the front, it NEEDS to be masked, fit a limiter in the rear.