Brake problems

[jimbob]

My car has developed a fault where it no longer has power assistance to the brakes!

The fault developed as follows:

1. Check Antilock Brakes light started coming on, everyother time i started the car. No noticeable difference to brakes. This went on for a week or two.

2. Check Antilock Brakes light stopped coming on for a week.

3. Started the car last nite, Anti Lock Brakes light came on as before, but now brake pedal is real hard and you have to press REALLY hard to stop the car.

I have read a couple of threads on this, what i need to know is what i need to test, in what order and how i test it..before i start spending big bucks!!

Why cant these cars have a regular vacuum servo!?!?!

Any help/suggestions realy appreciated! Thanks

 

[JoshMcMadMac]

Start by pulling the codes from the ABS module. If the amber ABS light is coming on then there are codes to be had. Otherwise you may want to consider how long it has been since the brake fluid has been changed. If it is much more than two years there is probably water contamination in there. You may have a bad accumulator, but I would pull the code(s) and possibly check the relay first.

 

[jimbob]

Hi JoshMcMadMac, Unfortunately i dont have a code reader for the ABS, i have one for the enigine. Can you recommend one that i need to get for it? I might try eBay. The brake fluid has not been changed for at least 2 years, so as you suggest i may start with that. One thing i do not understand is how contaminated fuild causes this problem? as i still have a firm brake peddle, although i have heard of this before happening before.

 

[JoshMcMadMac]

Hi JoshMcMadMac, Unfortunately i dont have a code reader for the ABS, i have one for the enigine. Can you recommend one that i need to get for it? I might try eBay. The brake fluid has not been changed for at least 2 years, so as you suggest i may start with that. One thing i do not understand is how contaminated fuild causes this problem? as i still have a firm brake peddle, although i have heard of this before happening before.

The engine code reader is the same for the ABS. Your manual will have instructions as well as code information. Cantaminated fluid has water, which in turn adversely affects the system, and can possibly cause your trouble.

 

[jimbob]

I checked my code reader, but mine does not do ABS. I even checked with the manufacturer.

I checked the motor relay, and that seems to be working fine, however..the problem seems to be that the pressure switch is not activating the relay. I shorted out the relay multiplug to simulate the relay operating and you could hear the pump start. I have not changed the fluid yet as you suggested (trying out options that involve less work first!!!) but could bad fluid cause the pressure switch not to operate correctly?

 

[JoshMcMadMac]

I checked my code reader, but mine does not do ABS. I even checked with the manufacturer.

The code reader is the same for engine codes and ABS codes; I assure you. I will have to check my manual to remember how to properly pull codes from the ABS, but I am certain that your tool is capable of this. A simple paper-clip can do the job, or a test light, so it is a simple process.

I checked the motor relay, and that seems to be working fine, however..the problem seems to be that the pressure switch is not activating the relay. I shorted out the relay multiplug to simulate the relay operating and you could hear the pump start. I have not changed the fluid yet as you suggested (trying out options that involve less work first!!!) but could bad fluid cause the pressure switch not to operate correctly?

If you are sure that the relay works, you might have a bad accumulator if the red brake light is on. Bad fluid tends to cause the unit to not stop running, as opposed to not running at all, but it is possible that the fluid is causing the fault. You will want fresh fluid regardless, so this is probably a good step to take.

 

[metz82]

similar problem

I am having that similar problem where the brake pedal becomes hard to push, and the cars braking power is basically cut in half and its a little dangerous to say the least.. seems to be that would be what I think is called the Hydro-Boost unit in my 90 lsc, anyone had this problem and if so is that a job that you might consider doing yourself? Also there are no check brake lights showing,
Thanks

 

[JoshMcMadMac]

Start by flushing the fluid.