13 replies to this topic

[Daze]

Hi all.

Got a bit of a weird problem, whenever I brake hard the rear wheels lock up before the front. Also, if im not braking hard you can just "feel" the rear brakes working before the front ones start to at all.

Ive bled the system in the correct order, I think (as per haynes manual). Front/rear split non-servo dual system which is r/n/s, r/o/s, f/n/s, f/o/s right?

I have jacked the car up at the back and the wheels spin OK (infact not really enough, since my handbrake is at 4 clicks..) However, one of my adjusters on the drum has seased, so I will replacing that.

I am planning on fitting a late-style servo to my system, along with new shoes, a pair of new rear wheel cylinders, kad quadrants, a twin cabled handbrake, new handbrake cables and a different bias valve since I have been told that I could have a knackered master cylinder and/or bias valve. (and may as well fit all that other stuff too).

But... could it be something else? More obvious? Am I doing something wrong!? Yes, i have one of those one-man bleed kits, but still get an "assistant" to help me and I manually close off the nipples each time.

Also, if im going to buy a pair of drum adjusters from Minispares shortly, is there anything else that it worth buying, at the same time, with regards to the braking system?

Up front I am running with Minisport 7.9 inch grooved discs & alloy 4 pot calipers.

[Wil_h]

Sounds like you bias valve is knackered.

[Daze]

Cool. I was thinking that too. This is the little thingy which has 4 pipes in & out of it mounted in front of the o/s suspension mount, right? If so, I got another one of those! ...

I shall try that (since its only a 10 min job?) and see if i get anywhere. Yet more brake fluid needed!!

Anymore ideas, etc?

[Jordie]

Dont you have to change the rear cylinders to a different bore or something if you fit some aftermarket front brakes. (think this is when converted from drums to discs)

Just an idea....

[Daze]

Indeed Ive just read the exact same thing on the Minispares website through one of their articles. I think I will getting a fully adjustable brake bias valve from Demon Tweeks, and ditching the standard pressure regulator all together, and at the moment not fitting a servo.

Anyone done anything similar?

Thanks again.

[Jordie]

Yes i believe the adjustable setup does help.

Or you can replace the rear clyinders with the correct bore size.

Now i think for the adjustable ones to be legal, mot-wise in a road car, you must not be able to reach it while the vehicle is in motion.

So therefore, you would probally have to fit the valve on the bulkhead or somewhere.

Thats *I THINK* not definate.

[Daze]

Cool! Im pretty sure that wrong though. A friend of mine has an adjustable bias valve right next to the drivers seat in his race car and it passed no problem. I guess its dependant on the MOT test centre.

Thanks for your help. Ill post back here once my brake overhall is done & if i get any further issues!!

[Dan]

No it is most definitely illegal for the driver to be able to reach the bias adjuster from the drivers seat on a road car.

[Jordie]

thought so, cheers for making that clear Dan.

[Daze]

Hm interesting! Cheers guys. May just have to hide the lever under a bit of MDF or something, might make a cover come next year when my MOT it due!

[Wil_h]

No it is most definitely illegal for the driver to be able to reach the bias adjuster from the drivers seat on a road car.

Interesting.

For race cars the Blue Book say something along the lines of "as long as the bias valve cannot reduce the braking power to less than 25% on one axle then it can be adjusted when running"

For sprint and hillclimb cars you cannot have the adjuster in reach.

[Daze]

Ive spoken with the guy that has the race car, and apparently his MOT tester didn't even see the adjuster! His is positioned slightly behind the drivers seat, and with a full bucket seat it is almost impossible to reach anyway, without moving yourself to the right and stretching down between the door pillar and bucket seat.

I shall probably put mine either on the passenger side, or as above and slightly behind the drivers seat, near the rear door pocket.

Thanks guys.

[chrisls]

If it were me, the adjustable one would be going where i took the old one out, won't that just be easier?

And definetly pass the mot.

[Daze]

True. Just dont look as cool! Hehe