Brake Problems!

[Beirut_Rover]

Hi Eveyone

My Disco is a 1998 with 85,000kms on it.

I am very unhappy with the brake performance I am getting. Most of the brake parts have been replaced in the last two years (master cylinder, rotors etc) and I have heavy duty brake pads fitted.

The dealership says the brakes do not get any better and they are great for a series 1 Disco, but I KNOW they were better before I drove it over a 2,100m high mountain! Thet seem to me to lose a little bit of performance everytime I take it up a big hill......

Any Suggestions??

Cheers!

[pavel]

Exactly why are you unhappy with the braking performance? Losing brake power after being in the mountains seem odd - sounds like it may be pressure related.

Have you checked the vacuum hose to the booster? There is, I believe a little vent somewhere on the booster, is it plugged?
Are you sure this problem didn't begin shortly after putting in those HD brake pads? In our Volvo, I noticed a definite decrease in braking power (longer stopping distances) immediately after switching to a HD pad.
What about the master cylinder - is it an OEM part or some other manufacture? I had a case years ago of installing a master cylinder only to discover the bore was a smaller diameter by 1/8 inch.

[Badger1]

If you haven't already done this...how about changing to stainless steel braided brake lines, get rid of the spongy rubber OEM ones. Change to better higher temp. brake fluid, re-bleed everything, especially the master cylinder if a new one was fitted(might be residual air in the lines in there). Then as pavel stated in the previous post get rid of the HD brake pads, get a compound with better initial bite. The downfall to a softer better biting pad is they will have to inspected and changed more often.

[Beirut_Rover]

Thanks Guys!

Pavel, I thought it might be pressure related too, due to the decreased performance after some serious mountain driving, that's why I asked the Dealership to re-bleed the brakes for me. They claim however, that it won't make any difference.

The master cylinder is an OEM part, and the problem was actually worse before I fitted the HD pads. Just after fitting brake performance was much better I thought until I did some more mountain driving and then it got progressively worse again.......

Badger1
As you mention changing to better higher performance brake fluid that is why I thought bleeding the brakes now might help? Unfortunately finding any higher performance fluid is going to be the issue (I am in Lebanon, I imported the HD pads myself from Australia).
I don't really want to go to the expense of fitting stainless brake lines seeing as I have to sell the car in a little less than a year anyway when I am going back to Oz....

Thanks so much for your replies!

[p76rangie]

You might want to check your wheel bearings as the can allow the wheel to move, which seperates the pads. Is it going down hills or up hills that cause the problem. Most brakes will overheat going down hills in an auto. You should pull it back a gear and use the brakes less.

Ian

[300bhp/ton]

I guess you are referring to brake fade?

High temp fluid and suitable pads will help. Also check what type of discs you have, some Discovery's have solid front disc's these will overheater easier than vented ones.

Also as mentioned, try using more engine braking if you're really giving it some stick. Locking the tranny in 2nd or 3rd on downhill decents will help a lot and reduce the braking force required with the pedal.

[Beirut_Rover]

Thanks 300bhp/Ton!

I am not just referring to brake fade. I am pretty sure it's normal to expect a little bit of that when heading down some big hills.

My problem is that the brakes never seem to "come back" once I am safe and sound on the flat again, and each descent seems to make them a little worse!

Help!?!?!?!?!?

[p76rangie]

With the heat you could find that either the pads or the discs are glazing up. This will explain why the brakes are getting worse as more glaze builds up. Check the discs to see it they have a shining polished look or a machined metal look.

Ian

[300bhp/ton]

Originally Posted by Beirut_Rover

Thanks 300bhp/Ton!

I am not just referring to brake fade. I am pretty sure it's normal to expect a little bit of that when heading down some big hills.

My problem is that the brakes never seem to "come back" once I am safe and sound on the flat again, and each descent seems to make them a little worse!

Help!?!?!?!?!?

That certainly sounds like brake fade, heat dispersal takes long than it does to build it up. My D90 used to cook the brakes big time so much so it dis-coloured my white steel wheels to an off white/yellow colour on the front.

It would however lock the wheels at 50mph if so desired.

Good pads/discs and high temp fluid it probably what you want, maybe some vented cross drilled discs like EBC or similar. Also make sure sure there's no air in the system or water. If the brake fluid hasn't been flushed for a while it won't help (topping up isn't the same thing). Water and/or air in the brake lines will give reduce braking power more pedal travel and less affect at slowing you up and will only get worse after each braking attempt.