ABS Problems at Low Speed

Jakg · 3rd April 2014, 17:47

When braking very very gently at low speeds (<15 MPH), I sometimes get ABS kick in very lightly.

Stopping from faster speeds is fine, and ABS kicks in normally if you go for an emergency stop.

Last time this happened (last week) I thought it was air in the system, and after a couple of hard stops it was all ok again.

Unfortunately its happened again driving back from work, and a hard stop hasnt changed anything.

Any ideas?

I'm changing the brake fluid this weekend anyway.

breakfastinsmethwick · 3rd April 2014, 18:06

I had a similar thing on a clio (yeh I know). It was the ABS reluctor ring fractured and loose on the driveshaft. I have no idea if R75 shafts have a separate ring on the CV joint or not though.

klarzy · 3rd April 2014, 18:08

Quote:

Originally Posted by Jakg

When braking very very gently at low speeds (<15 MPH), I sometimes get ABS kick in very lightly.

Stopping from faster speeds is fine, and ABS kicks in normally if you go for an emergency stop.

Last time this happened (last week) I thought it was air in the system, and after a couple of hard stops it was all ok again.

Unfortunately its happened again driving back from work, and a hard stop hasnt changed anything.

Any ideas?

I'm changing the brake fluid this weekend anyway.

Possibly the magnetic reluctor ring on your wheel bearing is breaking up or the ABS sensor is on the edge of failing for that wheel (front left or right).
Try a cheap sensor off the bay to eliminate that first before changing wheel bearings or looking at ABS valve.

VMax1000 · 3rd April 2014, 18:11

Quote:

Originally Posted by breakfastinsmethwick

I had a similar thing on a clio (yeh I know). It was the ABS reluctor ring fractured and loose on the driveshaft. I have no idea if R75 shafts have a separate ring on the CV joint or not though.

They haven't, reluctor ring is in the wheel bearing. Could be a bearing issue or a sensor issue. Difficult to tell.

But how do you know it's the ABS? Judder in the brake pedal can also be slightly warped discs. Not necessarily noticed at high speeds but present at low speeds. (I have the same on my car). Breaking from high speeds is fine, breaking from low speed feels a bit like a judder.

HarryM1BYT · 3rd April 2014, 18:43

Aside from all of the above, check the tyre pressures are correct. There is also a possibility of different tyre treads triggering the ABS due to slightly differing grip.

vindaloo · 3rd April 2014, 18:56

I had the same problem on my Tourer it was a corroded ring on the rear nearside, needed a new wheel bearing and problem cured.

pab · 3rd April 2014, 19:31

Quote:

Originally Posted by vindaloo

I had the same problem on my Tourer it was a corroded ring on the rear nearside, needed a new wheel bearing and problem cured.

Agree here Jim. The bearing breaks down and the ABS sences resistance. To identify which bearing is the issue, T4 is needed.

Jakg · 3rd April 2014, 19:39

Quote:

Originally Posted by VMax1000

But how do you know it's the ABS?

I get the noise, the pedal "twang" etc just like ABS.

Quote:

Originally Posted by vindaloo

I had the same problem on my Tourer it was a corroded ring on the rear nearside, needed a new wheel bearing and problem cured.

A new wheel bearing sounds expensive...?

Quote:

Originally Posted by HarryM1BYT

Aside from all of the above, check the tyre pressures are correct. There is also a possibility of different tyre treads triggering the ABS due to slightly differing grip.

All tyres are the same (Vredestein Ultrac Sessanta's) and pressure are ok.

vindaloo · 3rd April 2014, 20:07

Quote:

Originally Posted by pab

Agree here Jim. The bearing breaks down and the ABS sences resistance. To identify which bearing is the issue, T4 is needed.

Unfortunately didn't have my T4 when this happened and it was the fourth wheel checked, but I won't get the problem in the future as I'm now tooled up

klarzy · 3rd April 2014, 20:23

Quote:

Originally Posted by Jakg

I get the noise, the pedal "twang" etc just like ABS.

A new wheel bearing sounds expensive...?
All tyres are the same (Vredestein Ultrac Sessanta's) and pressure are ok.

Wheel bearing in garage £100 - £150+
DIY £30-£40 for a good bearing but 3 hours and a 10 tonne press are usually a must, you will also usually destroy the abs sensor getting it out if corroded in place so count another £12 for a cheapy to £60+ for a good one. You should get a new hub nut with the bearing kit.

Best in the garage for most...

3rd April 2014, 17:47	#1
Jakg This is my second home N/A Join Date: Feb 2010 Location: Suffolk Posts: 6,867 Thanks: 0 Thanked 397 Times in 302 Posts	ABS Problems at Low Speed When braking very very gently at low speeds (<15 MPH), I sometimes get ABS kick in very lightly. Stopping from faster speeds is fine, and ABS kicks in normally if you go for an emergency stop. Last time this happened (last week) I thought it was air in the system, and after a couple of hard stops it was all ok again. Unfortunately its happened again driving back from work, and a hard stop hasnt changed anything. Any ideas? I'm changing the brake fluid this weekend anyway.

3rd April 2014, 18:43	#5
HarryM1BYT This is my second home 75 Contemporary SE Mk II 2004 Man. Sal. CDTi 135ps, FBH on red diesel, WinCE6 DD Join Date: May 2010 Location: Leeds Posts: 17,273 Thanks: 2,160 Thanked 2,061 Times in 1,586 Posts	Aside from all of the above, check the tyre pressures are correct. There is also a possibility of different tyre treads triggering the ABS due to slightly differing grip. __________________ Harry How To's and items I offer for free, or just to cover the cost of my expenses... http://www.the75andztclub.co.uk/foru...40#post1764540 Fix a poor handbrake; DIY ABS diagnostic unit; Loan of the spanner needed to change the CDT belts; free OBD diagnostics +MAF; Correct Bosch MAF cheap; DVB-T install in an ex-hi-line system; DD install with a HK amp; FBH servicing. I've taken a vow of poverty. To annoy me, send money.

3rd April 2014, 18:06	#2
breakfastinsmethwick Gets stuck in Maintainer of sons ZT M47r Join Date: Dec 2013 Location: Shropshire Posts: 624 Thanks: 609 Thanked 124 Times in 100 Posts	I had a similar thing on a clio (yeh I know). It was the ABS reluctor ring fractured and loose on the driveshaft. I have no idea if R75 shafts have a separate ring on the CV joint or not though.

3rd April 2014, 18:56	#6
vindaloo Ex Owner MX-5 ND2 RF Join Date: Sep 2010 Location: Leigh Posts: 6,574 Thanks: 462 Thanked 799 Times in 524 Posts	I had the same problem on my Tourer it was a corroded ring on the rear nearside, needed a new wheel bearing and problem cured.