Brake balance question..

[kev131]

As regular followers of the forum will know my ongoing brake problems were resolved recently after having replaced nearly every component of the system.

However when testing my new firm pedal the rear brakes have a tendancy to lock before the fronts which is not the way it was before. While this feels great on a straight dry road I fear that sudden hard breaking on a corner in the wet will mean the loss of rear adhesion in a sudden and spectacular fashion. 

My mechanic teells me that the brake regulator can be adjusted but that it needs a special tool. Does anyone know what this is and where one can be found, along with any tips on doing the job...??

Thanks

[bolger]

I think it is shown in Haynes. As to the tool, I would ask US vendors.

[Thotos]

As far as I know brake balance regulators on Fiat 131's are not adjustable. If you are getting the rear brakes to lock before the fronts then I'd do something about it very quickly Kevin. That's a very bad thing to happen even in a straight line as once the rear brakes lock you'll get the back of the car travelling faster than the front and end up doing a 180 degree spin very quickly!  I would guess that the valve on your car doesn't work properly or could even be that your front brakes are not as efficient as you think; a firm brake pedal doesn't necessarily mean good brakes. You should first have the brakes tested on a rolling machine as used for MOT tests to establish how good they are and at what point the wheels lock. If the rear wheels lock easier than the front then check the front brakes. Some basic adjustment of the brake balancing valve can be achieved by bending the actuator rod (long rod from the valve to the trailing arm). Incidentally, my car does very well without a balance regulator valve.

[curt]

Hello All
I had this problem on one of my sports and it was the brake balance regulator at the back. I seem to remember there are two 13mm hex bolts on the side and you can swing it up or down to release pressure sooner or later from rear brakes . There is a static gap recommended by fiat but it was years ago and i cannot remember .
It could also be the master cylinder to pedal arm clearance is wrong -this would give the hard pedal and a short reach on the pedal itself to full lock up on the rears and fronts but mainly bias the rears . If you undo the master cylinder - two 13mms again behind is a small domed adjuster stud -If this does not have any clearance it describes the problems you are having and can also cause locking up of wheel cylinders and/or calipers
Dont know if it helps but its the only experience Ive had with rears locking up 

[Kennedy of Sixmilebridge]

Did you get this sorted Kevin, or is she still giving you brown trousers moments when braking ?

[kev131]

Hi Guys

Still got the problem but driving around it.

I've bought 2 regulators, both from Ricambio, one to fit and one as a spare hoping that it will "regulate" the problem.

My normal Fiat trained mecahanic is out of action at the moment - Can any experienced mechanic fit or adjust it ?

[eugene]

I had the same problem on one of my Lada Niva's, as you have Kev.I never worked on the braking system of a 131,however i presume the Lada braking system is a Fiat based one as Lada and Fiat are first cousins.After a long time i found the problem,it was a faulty equalizer for the back brakes.Hope this info is off help.Eugene

[Walezy]

You might want to fit a race brake regulator. They can be bought on ebay for about 50USD from wilwood and work very well. You will be able to adjust the brakes in the car by a lever or a knob(two versions available). The original fiat regulators are most of the time rusty and do not work. I use such regulators for years and never had any problems(now i have tilton in my fiat but it is a bit more expensive option, i used also wilwood in several cars i built and it works equally well).
Tomasz

[theredx19]

can you put up a link to wilwood as I am building an abarth eating Lada and would like a bit of bias to the rear see if she will diff out at 70mph plus.

[bax131]

For quite sometime now my 131 Series 1 brake is rather unreliable. The second pump on the pedal to feel the bite. Master cylinder, replaced. My mechanic suspects the servo, till then no tailgating  . Suggestions please.

[Thotos]

Servos usually either work or they don't so I don't think that's your problem. Then again I am not a mechanic while your mechanic is one!

Make sure there's absolutely no air in the system as that would cause the fault you describe. Also make sure your rear drum brakes are adjusted properly. Try driving with the handbrake pulled up half way and if the brakes feel much better then the rear drum shoes will need to be adjusted manually as the automatic adjusters don't always work.

[bax131]

Thanks. The brake works better when i pull it half way. I'll have it adjusted sometimes tomorrow.

Have a good trip to the Lake District. I've only seen it through pictures & maybe a bit of Wordsworth . Been to Queenstown and its beautiful lakes & fiords.

[curt]

Hey Kev
did you finally sort this out 

[Tas131]

The 131 has a load proportioning valve on the rear to reduce rear brake pressure as weight shifts to the front under braking. The valve is adjusted by loosening the 2 mounting bolts, it pivots on the bottom bolt as the top bolt slides in an elongated hole. According to the book, with the vehicle on a level surface, it should take between 600 and 800gm to push the proportioning valve rod off it's seat,

[cfont60]

I am about to have the brakes fixed in my new 131 Racing. Does any one have a photo of the Load Proportioning Valve and its rods?