1998 v70 Pulsing Brakes

t5rules · Post by **t5rules** » 02 Jul 2014, 16:13

Hi, can some one help me please? the brakes have started pulsing when applied. I replaced discs and pads and droplinks and it didn't make a difference. There is slight knocking noise from front far side but checked bushes and can't see any that are worn that bad. I checked abs and rear brakes and are fine. its coming from front. Could it be bottom ball joint? At high speed under heavier braking it all most shakes..any ideas? Cheers

Post by **Ozark Lee** » 02 Jul 2014, 16:20

Replace the front rotors and your problem will go away.

Please also see this post:

https://www.matthewsvolvosite.com/forums ... =1&t=44724

I cleaned up the sentences for you.

...Lee

t5rules · Post by **t5rules** » 02 Jul 2014, 16:28

hi,I have put new ones on and did not make any difference.

Post by **Ozark Lee** » 02 Jul 2014, 16:42

Do they vibrate at the same frequency as a revolution of a wheel or is it a rapid buzzing pulse? If it is the latter then the ABS system is at fault.

...Lee

t5rules · Post by **t5rules** » 02 Jul 2014, 16:44

They go with the revolution of the wheel.I disconnected the abs and it is the same.

Post by **Ozark Lee** » 02 Jul 2014, 16:49

What you are describing sounds exactly like warped rotors but since you changed them the only thing I can think of is perhaps a bad front hub.

...Lee

t5rules · Post by **t5rules** » 02 Jul 2014, 16:55

I was told it might possibly be bottom ball joint but can not see any play in bush.

difflock54 · Post by **difflock54** » 02 Jul 2014, 19:03

Are the brake pads and the retainer spring clips fitted correctly ?

Post by **Ozark Lee** » 02 Jul 2014, 19:45

The bad ball joints tend to create more of a "wandering" sensation at highway speed and can manifest itself as vibrations at speed but the symptoms normally aren't amplified at all by braking. The way to test for bad ball joints is to jack up the car and push the wheel side to side and up and down. There shouldn't be any perceptible movement. Some side to side movement can be as a result of bad tie rod ends as well as a bad ball joint or a bad wheel bearing hub.

If there is movement you need to feel around to fell where the movement is occurring, that will be the part that is bad. On good OEM control arms it is usually the ball joint that fails on the control arm before the bushings back at the subframe mounts. On some of the cheaper aftermarket control arms it is a race to see which will fail first, the ball joint or the bushings. By 100,000 miles, (160,000 km) the control arm ball joints are typically worn out. Local road conditions can greatly change that life expectancy.

...Lee

t5rules · Post by **t5rules** » 03 Jul 2014, 02:05

all brakes are fitted correctly and there is no play on any wheels or bushes that I can see..