Brake Bias Set Up On Twin Master Cylinder With Brake Bias Bar

[Guest danny88]

Hey guys, another post about brake bias,

Thanks for all the replies on my last post, very helpful!

Just wandered if anyone could tell me or send me some pictures regarding their set up of the bias bar? What are the figures/ percentage for front, rear braking? If anyones got a picture of their bar set up that passed iva that would be much appreciated so I could set mine up too? I can't get the car to a MOT test station before the test. At the minute my bias bar is pretty much set in the middle. I have drums on the rear and sierra callipers on the front. Does the front need more braking force or the rear?

Thanks,

Danny

[knights_templar]

Its in section 09E of the testing manual. But it looks a though it is a percentage of vehicle weight. haven’t time to extract and post at moment, but will if you require later.

 

as a rough set-up, jack up front and rear of car, have someone apply the brakes, slowly, until the front wheel can not be turned by hand, check the rear wheel can just be turned, if not adjust to give more load to front.

 

take your locking wire and tools to the test, most testers will allow tweaking, as long as it is locked when it leaves the test centre.

 

It may be prudent to do some research on now the system works, so that you appear confident in adjusting to their requirement.

 

Not that lack of knowledge can be a fail, but it may reduce the lecture on adjustable bias systems for road use

[Longboarder]

From my own experience with a bias bar the first requirement is enough play to allow the bar to pivot in its housing and big enough penny washers to avoid catching the shoulders of the push rod housings in the pivot housing. Next the rear cylinders need about a quarter of the fluid of the front calipers so the bar should be set well forward on the rear cylinder and back on the front cylinder. It doesn't start square in the pivot housing. This is all before you even think about bias pressure. Quick draw of what I mean below. On pushing the pedal forward you will find the bias bar position will have reversed with the front cylinder side fully forward and the rear back. The push rods will be unequal lengths when adjusted. Usual to use .75 master cylinder for rear and .625 for fronts.

 

Nigel

Edited November 14, 2014 by Longboarder