Brake pedal 'pulsing' at slow speeds.

Graham1961 · 12th May 2016, 22:22

Hi All.

Need a wee bit advice here....my 75 saloon 1.8 has just developed a wee braking issue.

At slow to moderate speeds and you brake gently there is a kind of 'pulsing' feel through the brake pedal, the brakes work fine and i cannot see any signs of fluid leaks (brake fluid is clean) and the discs appear to be in good order.

At first i thought perhaps warped discs, but there is no vibrations felt through the wheel and there is no ABS warning light coming on.

Any advice as the MOT is due next month.

Thanks for any help in advance.

marinabrian · 12th May 2016, 22:57

Quote:

Originally Posted by GRAHAM1961

Hi All.

Need a wee bit advice here....my 75 saloon 1.8 has just developed a wee braking issue.

At slow to moderate speeds and you brake gently there is a kind of 'pulsing' feel through the brake pedal, the brakes work fine and i cannot see any signs of fluid leaks (brake fluid is clean) and the discs appear to be in good order.

At first i thought perhaps warped discs, but there is no vibrations felt through the wheel and there is no ABS warning light coming on.

Any advice as the MOT is due next month.

Thanks for any help in advance.

Graham, this is likely to be a plausibility issue, where the magnetic flux of the rear wheel bearings is interrupted by rust formation where the stub axle passes through the brake backplate.

99.9% of times a clean up in that area is all that is required, however strange results were noted recently when a car was fitted with different size tyres on the front and back

T4 will point you in the right direction though

Brian

murphyv310 · 13th May 2016, 07:44

Hi.
I'm with Brian on this, COA developed the same problem after driving at slow speed on a really bad road. There was rust from the rear backplates that had clogged up between the sensor and bearing. A good clean up resolved the problem for some time but it come back a few months later, so the same was done again.
I believe the new owner has the problem again so It looks like a new back plate is in order.
It won't fail the MOT as the light doesn't come on and the rollers don't rotate fast enough to bring the effect on.

wullie480 · 13th May 2016, 08:23

I'm with Brian & Trevor, I've had it on the wife's zt a few times rear sensor or bearings magnetic pick up become clogged\blocked with metallic particles.
A quick clean up solves it till the next time

Avulon · 13th May 2016, 12:49

Quote:

Originally Posted by marinabrian

r strange results were noted recently when a car was fitted with different size tyres on the front and back

T4 will point you in the right direction though

Brian

About time I replaced those front tyres then, Only thing is I was expecting to be replacing them December/January - But they steadfastly refuse to wear out at the previous rate. So now I have worn 45 profiles on the front - and barely scrubbed in 50 profiles on the back. Pulsing comes and goes but mostly not at all at the moment, but still get an occasionally sudden drop and increase in braking force when coming to a halt.

T4 didn't show a problem earlier in the year - but that was static not rolling.

Leafie · 13th May 2016, 19:36

This can also happen if you don't travel/use the brakes much.

This might not be the answer many would offer up but it worked for me. Get yourself out of the way of traffic and brake aggressively from a good speed. Do it 3-4 times. I'm not sure, but I'm guessing contamination of the disc surface occurs from little use/light braking.

Alex30013k · 13th May 2016, 20:30

My mum moaned about her zt the other day saying that the brake peddle judders when she breaks, went out and had a look all disks rusty and uneven, took it for a thrashing, few 70 down to 0 hard stops and soon sorted them, #
She has started to drive like miss daisy as she is getting older.

Leafie · 13th May 2016, 20:53

Yep. Simple solutions fix it 90% of the time!

Quote:

Originally Posted by Alex30013k

My mum moaned about her zt the other day saying that the brake peddle judders when she breaks, went out and had a look all disks rusty and uneven, took it for a thrashing, few 70 down to 0 hard stops and soon sorted them, #
She has started to drive like miss daisy as she is getting older.

Ravinder · 13th May 2016, 23:22

It's worth trying a few hard stamps on the pedal Graham from a higher speed. Won't do any harm. Try some prolong braking. Gently use tye accelerator at the same time. And a few hard braking from higher speeds on a quiet road somewhere, even until the ABS kicks in. See if that helps.

lesron · 14th May 2016, 16:20

Had similar problem but thanks to you all a quick strip down at the rear hub and low and behold the back plate is rusting away gave it a good clean out , and removed rust around bearing face ( drivers side ) greased the face tnen did the same on passanger side, back plate was in good condition but cleaned up bearing face , all works as it should

12th May 2016, 22:22	#1
Graham1961 Moderator / RS East Scotland Rover 75 1.8 Conn Se saloon Join Date: Nov 2007 Location: North Berwick, East Lothian Posts: 4,738 Thanks: 4,143 Thanked 753 Times in 563 Posts	Brake pedal 'pulsing' at slow speeds. Hi All. Need a wee bit advice here....my 75 saloon 1.8 has just developed a wee braking issue. At slow to moderate speeds and you brake gently there is a kind of 'pulsing' feel through the brake pedal, the brakes work fine and i cannot see any signs of fluid leaks (brake fluid is clean) and the discs appear to be in good order. At first i thought perhaps warped discs, but there is no vibrations felt through the wheel and there is no ABS warning light coming on. Any advice as the MOT is due next month. Thanks for any help in advance. __________________ Graham.

13th May 2016, 07:44	#3
murphyv310 This is my second home Hyundai i10 998cc Join Date: Mar 2012 Location: Kilmarnock Posts: 6,602 Thanks: 2,088 Thanked 2,298 Times in 1,349 Posts	Hi. I'm with Brian on this, COA developed the same problem after driving at slow speed on a really bad road. There was rust from the rear backplates that had clogged up between the sensor and bearing. A good clean up resolved the problem for some time but it come back a few months later, so the same was done again. I believe the new owner has the problem again so It looks like a new back plate is in order. It won't fail the MOT as the light doesn't come on and the rollers don't rotate fast enough to bring the effect on. __________________ Cheers from Trevor MM0KJJ

13th May 2016, 08:23	#4
wullie480 This is my second home 1 Join Date: Dec 2010 Location: Banned Posts: 5,196 Thanks: 528 Thanked 1,022 Times in 786 Posts	I'm with Brian & Trevor, I've had it on the wife's zt a few times rear sensor or bearings magnetic pick up become clogged\blocked with metallic particles. A quick clean up solves it till the next time __________________ [SIGPIC][/SIGPIC]

13th May 2016, 19:36	#6
Leafie Regular poster MG Join Date: Oct 2009 Location: Bonne Nuit Posts: 48 Thanks: 0 Thanked 14 Times in 7 Posts	This can also happen if you don't travel/use the brakes much. This might not be the answer many would offer up but it worked for me. Get yourself out of the way of traffic and brake aggressively from a good speed. Do it 3-4 times. I'm not sure, but I'm guessing contamination of the disc surface occurs from little use/light braking.

13th May 2016, 20:30	#7
Alex30013k Posted a thing or two Rover 75 Saloon 2.0 CDTi Conn Se Join Date: Nov 2006 Location: Ashford Kent Posts: 1,560 Thanks: 17 Thanked 29 Times in 21 Posts	My mum moaned about her zt the other day saying that the brake peddle judders when she breaks, went out and had a look all disks rusty and uneven, took it for a thrashing, few 70 down to 0 hard stops and soon sorted them, # She has started to drive like miss daisy as she is getting older.

13th May 2016, 23:22	#9
Ravinder This is my second home Rover 75 saloon x2, Rover 75 Tourer x2, Rover 220 Coupe Turbo Join Date: Aug 2010 Location: Kirkcaldy, Fife Posts: 9,038 Thanks: 2,278 Thanked 2,852 Times in 1,718 Posts	It's worth trying a few hard stamps on the pedal Graham from a higher speed. Won't do any harm. Try some prolong braking. Gently use tye accelerator at the same time. And a few hard braking from higher speeds on a quiet road somewhere, even until the ABS kicks in. See if that helps.

14th May 2016, 16:20	#10
lesron Avid contributor rover 75 saloon and tourer Join Date: Jul 2015 Location: Hythe Posts: 162 Thanks: 31 Thanked 9 Times in 9 Posts	Had similar problem but thanks to you all a quick strip down at the rear hub and low and behold the back plate is rusting away gave it a good clean out , and removed rust around bearing face ( drivers side ) greased the face tnen did the same on passanger side, back plate was in good condition but cleaned up bearing face , all works as it should