Bedding in VR disc brakes problem

[kswenson]

I have just replaced all four rotors and pads on my VR executive, but they just don't seem to be bedding in. I ftted DBA standard rotors and Bendix Stealth pads, but the car just doesn't want to stop. All have been fitted properly and the calipers etc are working properly. I have now done over 220 kilometers over the past three days trying to bed them in, but the brakes are still lousy. I have no emergency stopping power at all. I have removed the front calipers since and cleaned them and gave them a rub with sandpaper but still no better. Three brake companies I spoke to didn't seem surprised that the brakes don't work too good after changing all four brakes, but can only advise me to keep beeding them in. (brake accelerate brake etc).

If they don't come good by the weekend I'll change the pads again for a different brand and see what happens. However, is there any way of telling whether the master cylinder is applying the correct pressure to the wheels? There is no air in the hydraulic line because they don't actually pump up harder when pumping the pedal.

Has anyone else experienced this sort of problem when changing all for wheels at the same time?

 

[Brett_jjj]

They can take time to bed in.Id have thought they would have bedded in by now though after that amount of k's..Try to do some heavy stops from around 70 km/h.Dont come to a complete stop though,keep the car moving.Do this a few times in succession or until you can smell the pads getting hot.Then drive slowly(40k's),trying not to brake until they have had a chance to cool right down again.They should start to come good after this.

 

[kswenson]

Thanks Brett. I have just been out on a quiet road again and tried bedding them in. The road was wet and i'm starting to get one front wheel trying to lock up and there's a slight improvement. I would have thought the back wheels would have locked up at some stage, but that hasn't happenned yet. When I got back home I could smell all the brakes on all four wheels, so they are working. I'll let them cool down and go out on the road again to see if there's an improvement. I didn't think it would take this long. The reason I asked about the master cylinder is because I bought the car new in 1993 so I know the master cylinder is original. Is there any advantage in changing the brake fluid perhaps?

 

[RX25SE]

Did you clean the protective coating from the discs? With a non mineral based cleaner?

It is not uncommon to have poor braking when replacing all rotors and pads. After 200+km they should be near OK.

Did the brakes feel OK before the job? Chances are the hydraulic/booster systems are fine.

TBH Im not a fan of Bendix.
It would be interesting to see if a pad change solves the problem.

 

[kswenson]

Yeah, I cleaned them all down with CRC brake cleaner. I know I did everything right, I'm just concerned about how long it's taking to get decent brakes. I did notice that the Bendix Stealth pads have large bevelled edges at both ends and in the middle, which is obviously their solution for quiet brakes. However, the pads I pulled out (which have now gone in the rubbish) had a lot more flat surface against the disc. Maybe getting another brand of pads is the solution. After this I think my opinion of Bendix is going to be reduced somewhat. Before I did the brake change the brakes were OK, just that the pads were worn. The rotors weren't too bad, but I decided to renew the lot just bring it all back to new.

 

[James39]

Perhaps giving the brake system a flush and a bleed will help matters?

 

[delcowizzid]

depends on the pads a lot i allways used to run metal kings in all my cars bad in town had to push the pedal hard but when in the windy stuff hard on the brakes and getting heat in they are great opposite goes for the cheapo pads i run now good when cold bad when hot

 

[kswenson]

Hi James. I really don't think the hydraulic side of it is the problem, but it's something to consider. The fluid was last changed about 8 years ago, so it wouldn't do any harm. Thanks for your help.

 

[kswenson]

If I decide to change the pads for a different kind, what would you suggest. About 80% of my driving is at 100ks and 20% suburban traffic. I don't care what they cost, just so long as I can have good stopping power when needed. They are standard rotors.

 

[tezza]

Whats your brake pedal travel like?
Cant hurt to change the brake fluid especially if it 8 years old.