Brake performance

[rudi]

I am still looking how to improve the brake performance on my fast road TR3A (post 60K). I have quality plain disks with Green stuff pads at the front and standard liners at the back. The standard B-type calipers are reconditioned 2 years ago and the rear cylinders are new since last year. Pedal feel is firm when cold but there is increased travel after a while (twisty roads, fast road driving). Brake fluid is standard DOT 4 and I believe the system is bleeded properly.

I definitely want to stay period meaning that the system should stay original for reason of some rally regulations. The only thing I can think of is to change the brake fluid to racing standard or DOT 5.1, install Alfin drums and ev. Mintex liners, eventually change the disks for slotted ones (stand. size not vented). I don't know if one of these will really improve the brake performance (shorter brake distance, no or less increase in pedal travel) and if they are worthwile to invest the money. Maybe I am just looking for something that is not there and my expected standards are too high? Any advice from the racers side maybe?

Regards, rudi

[JRCWeedon]

I am still looking how to improve the brake performance on my fast road TR3A (post 60K). I have quality plain disks with Green stuff pads at the front and standard liners at the back. The standard B-type calipers are reconditioned 2 years ago and the rear cylinders are new since last year. Pedal feel is firm when cold but there is increased travel after a while (twisty roads, fast road driving). Brake fluid is standard DOT 4 and I believe the system is bleeded properly.

I definitely want to stay period meaning that the system should stay original for reason of some rally regulations. The only thing I can think of is to change the brake fluid to racing standard or DOT 5.1, install Alfin drums and ev. Mintex liners, eventually change the disks for slotted ones (stand. size not vented). I don't know if one of these will really improve the brake performance (shorter brake distance, no or less increase in pedal travel) and if they are worthwile to invest the money. Maybe I am just looking for something that is not there and my expected standards are too high? Any advice from the racers side maybe?

Regards, rudi

 

Hi Rudi

The closest comparison I can relate is my old TR4 which had an identical set up to that you describe i.e. green stuff,standard discs and standard rear. Whilst the car was fairly light 920kg I had no problems at all and would suggest that alfins are a waste of (quite a lot) money unless you are doing 10 lappers. What could be affecting your pedal travel is "pad knock off" do the front wheel bearings need adjusting? Yellow stuff pads will withstand heat more but I cannot imagine that you need them with the use you describe.

Regards

John

[Don Elliott]

Rudi - When hot and on twisty race tracks, the guys in USA who race TRs have developed a stronger spindle stud for the front wheels with a spacer tube to make it even more solid. What happens is the original spindle stud bends in the fast turns and the caliper pistons move back so they had to tap the brake pedal just before they arrived at the next hard corner to re-set the piston and brake pad back onto the rotor. Now with the new set-up, the spindle doesn't flex and the piston stays close to the rotor.

[Nigel C]

I started out with all standard kit except whilst restoring I fitted s/steel braided hoses and silicon brake fluid form day one. Then about 12 months ago I converted mine over to swirllie discs and green stuff pads. I've rebuilt the old big bomb shaped callipers with genuine stanpart seal kit (as I was advised by a calliper specialist and good friend that a certain well know supplier's kit wasn’t worth the time to fit....and after my last encounter with them I agree!!) and the brakes are that good I'm not going to fit a servo. The pedal is furm and I put this down to the draided hoses. I can lock up all four wheels at once if I want to.

I do find and have had this from the start (8 years on the road) that when parking etc lock to lock that the pedal then goes down a considerable way first time. I thought perhaps it was something flexing but didn’t think it could be the stub axles.

 

On the other matter mentioned I purchased a new set of 10 inch drums as advertised lately in the Traction etc. they dually arrived as requested. I painted in heat resistant paint and fitted them.....but when I came to put the 2 retaining counter sunk screws in they sat 2mm proud of the face of the drum and when the bolt on knock on is fitted it wobbles on the two raised points!!!

It has taken so far 7 weeks to get an answer and supposedly a correction sorted out.

They have checked the stock and "wat ya know" there all like it. I was told that if I posted mine back (at my expense) that they would check them and send me a replacement...unpainted. b**l**ks.

In the end they were supposed to be picked up, remachined and brought back. I had a call to say "he" would collect Wednesday night, so jacked her up, took them off and waited...and waited no show.

By Friday I had had enough and took them to my friendly engineer/calliper builder and he machined a drill bit and drilled the drums.

I have refitted them and I'm once again wizzin about.

But why all this grief...I bought them in good faith...never ever again!!!

This is a constant problem with this major supplier It's "their margin" no other factor involved. Outsourced items to the cheapest manufacture to obtain the best margin. I'm sick of it. I will happily pay good money for good reliable items. ones that I don’t have to as in the past re-machine, replace, glue, weld, repaint or (and you'll love this one) fail an M.O.T. because a suspension part has only lasted 3,000 miles!!

Thank god they don’t supply the aviation industry.

(Sorry for the rant but bygum I feel better!)

[RogerH]

Hi Don,

your reply to Rudi regarding the bendy studs etc has solved an iritating problem I've had for a while.

On this years TR Isles Tour I found the brakes were getting poor going down very steep hills. I had the fluid changed as I suspected water contamination. This did the trick but I then found I was having to 'tap' the pedal prior to any serious braking.

When I got back to London I bled the brakes but still the problem. I bled them again, and again. I changed the rubber flexible brake hoses for metal braided and bled them again, and again, and again.

Eventually the car went for its MOT and failed on a front lefthand wheel bearing.

Exactly as you said, the 'slop' in the bearing allowed the disc to knock the pistons back into the caliper thus requiring the pedal to provide extra travel each time brakes were required.

 

If you suffer unexpected brake pedal travel check your bearings.

 

 

Roger

[North London Mike]

Hi Rudi

The closest comparison I can relate is my old TR4 which had an identical set up to that you describe i.e. green stuff,standard discs and standard rear. Whilst the car was fairly light 920kg I had no problems at all and would suggest that alfins are a waste of (quite a lot) money unless you are doing 10 lappers. What could be affecting your pedal travel is "pad knock off" do the front wheel bearings need adjusting? Yellow stuff pads will withstand heat more but I cannot imagine that you need them with the use you describe.

Regards

John

 

 

Hi Rudi, like John I can only relate my experience with my TR4. GREAT brakes, standard, but new and carfully put together with braded hoses and Green stuff up front and Mintex at the rear. Even on track days they hold up, the only thing I did was to fit the optional servo which just protects my sanity when I transfere out of the company Audi into the TR

 

I too can lock up all four wheels any time I please. Doesn't get much better in a road car

 

Disc knock off is a known problem and Revington, I think, do a kit ?

[Richardtr3a]

I bought a new set of 10 inch linings and they were not round. I took them back and just said not wanted. They were supposedly made in Birmingham.

Now I have some old original shoes and some linings bought at Beaulieu and will soon have brakes that do not seize up after a few weeks of rest and do not get red hot without being used.

There is a lot of rubbish out there. Don't get me started on regulators.

[Don Elliott]

Richard - When I want to get new linings mounted onto original bases, I take the drums with me and ask for the shop that does the re-lining to make them match the drums. I never had a problem. My own linings for my 10" drums have been on the car for 97,000 miles and they look like they have worn about 25%.

[rudi]

Thanks for all the replies so far. I believe the "problem" is indeed pad knock off. Revington is doing a kit RTR3463K called "bearing spacer kit". Does anybody have any experience with these or can tell how it looks or works. Their webpage is not giving much detail.

Cheers, Rudi

[marvmul]

Thanks for all the replies so far. I believe the "problem" is indeed pad knock off. Revington is doing a kit RTR3463K called "bearing spacer kit". Does anybody have any experience with these or can tell how it looks or works. Their webpage is not giving much detail.

Cheers, Rudi

I've bought such a kit directly from Jack Drews : I can provide the purchase details if you like.

The result is very good. The spindles and outside nuts are bigger too.

[Tr4Tony]

Rudi

 

there is quite a lot you can do to make the brakes work well on a 'legal' rally car;

 

Firstly at the front the quality of discs is variable and i would recommend that you get the best you can. Brembo make a solid disc (FIA legal) that is excellent. LUCAS TRW make a drilled and slotted disc (which isnt rally legal over here) and Im just about to try them out.

 

Secondly pad 'knock off' is a problem as the stub axles bend in hard cornering, forcing the pad back into the caliper. The anti knock kits are essential - there are three that I know of and all work well. Big stub axles and alloy hubs are good news too, but cost quite a bit.

 

Thirdly the standard 16PB type calipers seem to work well if maintained properly - difficult to get a rally legal alternative for a TR.

 

Fourthly ..... PAGID make a pad in their RS15 material which ive found to be excellt, if not a little hard on the discs - hence my first comment. Ive found that Green Stuff pads glaze quickly. Hawk pads are also useful, but need careful bedding in and getting up to temperature before they really work properly. On a rally car this doesnt work too well. They also dont like getting wet.

 

On the rear ive had some real fun. The commercially available 9 inch aluminium drums can be made to work well with some careful adjustment. I run kevlar race type rear brake linings on standard shoes and they seem to be the best available within reasonable cost.

 

A dual curcuit system tht allows some adustment of the front / rear bias is also helpful. I run about 75% front / 25% rear brakes.

 

Regards

 

Tony

[Nigel C]

I've bought such a kit directly from Jack Drews : I can provide the purchase details if you like.

The result is very good. The spindles and outside nuts are bigger too.

 

Can you give me details of this kit please, got to worth a go.

[david ferry]

Nigel,

 

Details here Jack Drews

 

David

[rudi]

Hi guys, thx for all the replies so far. Although not cheap, but the low USD-rate makes it attrctive anyhow to buy now, I want to go for the Jack Drews solution. Marcel, I guess I will need to order the complete kit at 290 USD and not only the stub axles?

Conc. the green stuff, I intend to agree with Tony. They have a better bite than standard, but seem to generate a lot of dust and intend to glaze (at least on my plain disks).

The rear standard liners (Moss) seem to touch the drums at the adjuster side when adjusted thightly and when spinning the wheel by hand . Loosing them up so that the wheel spins 100% free gives a big(ger) pedal travel. Should one find a compromise here or can they slightly contact the drum (w/o heating up too much) as the front pads do?

Cheers, Rudi

[Don Elliott]

Nigel - I'll bet a Canadian dollar that Dean Tetterton in Richmond, Virginia has the same front spindles in his racing Peerless. Ask Dean or Uncle Jack could tell you as well.

[Nigel C]

Nigel - I'll bet a Canadian dollar that Dean Tetterton in Richmond, Virginia has the same front spindles in his racing Peerless. Ask Dean or Uncle Jack could tell you as well.

 

jack Drews or standard?

[Richardtr3a]

Hi guys, thx for all the replies so far. Although not cheap, but the low USD-rate makes it attrctive anyhow to buy now, I want to go for the Jack Drews solution. Marcel, I guess I will need to order the complete kit at 290 USD and not only the stub axles?

Conc. the green stuff, I intend to agree with Tony. They have a better bite than standard, but seem to generate a lot of dust and intend to glaze (at least on my plain disks).

The rear standard liners (Moss) seem to touch the drums at the adjuster side when adjusted thightly and when spinning the wheel by hand . Loosing them up so that the wheel spins 100% free gives a big(ger) pedal travel. Should one find a compromise here or can they slightly contact the drum (w/o heating up too much) as the front pads do?

Cheers, Rudi

The rear shoes are not supposed to touch in one place and make the drums hot. I offered up the new against the old and found a different radius. It is only small and could probably be improved by filing the end of the shoe. But I don't want to do this.

 

I am having old shoes relined by someone who knows how to do it ,when I find him.

 

Good luck

Richard

[marvmul]

To order parts of Jack Drews, you have to send an e mail, I suppose you have to buy the complete kit (spindles + distant pieces and shims. The bearings are not included, but these are the standard ones).

 

Tony : can you give a brand name of the Kevlar linings for the rear brakes?