Brake Bias

[Guest old_timbo]

Latest test run has convinced me that the brake set up is bordering on dangerous. The rear wheels lock up long before the fronts get anywhere near. Bad enough on a flat, dry, hot road, but the first time it gets greasy I'll be through a hedge backwards. Set-up seems to be standard 2.0l Sierra i.e servo, discs and drums. No bias valve of any type is fitted, so I guess I need to fit one.

What does the team think I should fit? Stick with standard Sierra (anyone got one?), or fit some type of adjustable aftermarket device now that SVA is not an issue?

[Guest salty_monk]

Most people don't have a bias valve I don't think... I didn't & survived 2 track days without locking up the rears or probs like yours. Perhaps there is something else wrong? maybe your front pads are glazed??

 

You can get the ones that restrict flow but they are not supposed to be that great... to do it any other way I think you need a split circuit but I could be wrong.

[Guest chris brown]

There was at one time on build tips a modified mini valve to make it adjustable (come on guys someone must have it) but I am surprised you are having this problem. I felt that I did not have enough braking on the back (9" drums) so I removed the valve. I now have discs on the back but still have no valve fitted and the fronts lock first in fact I don’t think I have ever locked the backs on the road, only on the MOT break test

[swan]

chris

 

Its on the dave andrews web site which is listed on the nw hoodies site

 

http://hometown.aol.com/dvandrews/

 

swan

[Guest chris brown]

Cheers Swan I knew it was around somewhere.

[Guest roverT]

I am building a DOHC with discs all round. I haven’t had my car SVA tested yet but have spoken at length to the testers at Derby who have found that many of the cars fitted with discs all round are over braking at the rear. I tried to source the mini valve to mod as per Dave Andrews site but without success, it's no longer available new and there are precious few Minis in scrap yards. I have fitted a Wilwood proportioning valve, about £45.00 from, http://www.hispecmotorsport.co.uk-index.htm, to the rear hydraulic line, which will be locked in position for the SVA.

[Guest salty_monk]

The specialist mini suppliers must still do them... Their support is pretty comprehensive. I'd ask on the mini owners club forum, there must be one!

 

http://www.miniownersclub.co.uk/

 

http://www.smoc.co.uk/

 

http://www.norfolkminiownersclub.btinternet.co.uk/

 

http://www.bmoc.carlovers.co.uk/

 

http://www.lsmoc.org/

 

and there are more....

[Guest mickmellors]

the brake bias valve (along with fuel pump etc) on my car (built by others) was fitted on top of the chassis member in the boot area with plumbing coming up one side and down the other side of the chassis member which was making it very difficult to line the boot out ready for use. Wanting to move it out of the way I sought advice on where best to relocate it only to be advised to remove it and simply replace it with suitable fittings to join up the plumbing gap. Since this I have aske 4 others and only one has it in place - unsure of who is on drums or discs though.

[Guest Battery Bill]

Mick

We have a disk drum set up and are very happy with it, we did not fit the compensating valve or the servo, We put a new set of shoes on the back and a set of EBC Green Stuff pads up front and they work a treat. SVA were fine as well.

 

It was funny watching the SVA bloke on the brake test rig testing the brakes then switching the engine on, frowning a bit turning the engine off then back on Until I told him "No Servo mate"

[Guest old_timbo]

Hmm! My brakes were all new and have done about 1200 miles so look nicely bedded in. Strange that other folk can get away with no compensator and I can't. I'm getting suspicious now. I can't see any compensator in the engine compartment or up the gearbox tunnel, but I wonder if there is one tucked away up the back somewhere. If so it might be at the wrong angle or even plumbed in the wrong way round which would explain things. Guess I'd better get the ramps out for a really good check. Assuming all is as it should be, I like the idea of the modified Mini compensator. Courtesy of a Mini obsessed son, we have mountains of Mini stuff I can sift through so I might have one to mod already. Think the one needed will be early, as from the mid 80's onwards Mini's had dual line braking systems with a bulky system balance valve that was mounted on the front bulkhead. Think this might have been when front discs and 12" wheels became standard.

[nicko]

Hi all, There's a Mini specialist in Sheffield called Minibitz (or s), they are at 101 Albert Rd, Heeley, Sheffield, South Yorkshire S8 9QX

Tel: 0114 255 4630

 

Hope that helps someone.

Nicko

[Guest paul thompson]

I fitted the PCRV valve from a a Metro. You need a special nut for it though because you need a female nut with m12x1.25 thread and hole for 4.75 mm brake line. Quite rare but available. The metro valve cost me £2 from a scrappy and the nut I got off a freind that works for a brake tube company. It works really well, doesn't care where in the rear line you put it. If the master cylinder had had m12x1.25 tapping it would have gone in there. The other end is just standard m10 x1. It's held in the car on the cross member at the back of teh engine bay with a rivetable cabletie. Brake performance on my car is excellent and onbly locks the fronts when braking very hard.

I'd reccomend it as an easy fix. Not adjustable so might not be so great for track days etc. But how many of them are you going to be doing?

 

Paul

[IanS]

What type of pads do you have at the front. I have seen some cheep pads that glazed up just looking at them and then were useless, binned them and fitted ferodo ones, problem solved.

 

Or am I teaching grandmother to suck eggs??

[Guest Andy Rathbone]

i have the small 1.6 rear drums and Xr4x4 disk and calipers on the front, and the servo, yes it stops good and it passed sva no bias this or that.

 

ohohoh mini bits i realy need the loom connector plug to go into the wiper motor if any of you mini fiddlers have one or know where i can one, its a 5 pin doodaa

cheers

[Longboarder]

You can make an acceptable replacement by greasing the inside and pins with vaseline, fitting the wires using the 4.8mm spades and then filling the space with sikaflex and letting it set. If you are at the stage to wire it up you may never need to take it apart again but mine works fine four years down the road.

 

Nigel

 

PS I don't have a brake compensator, vented front disks and drum rears from a 2.0L sierra.