Rear ABS Sensor and Reluctor Ring

[Guest]

As I have a little time to kill I thought I would recount a recent adventure with my S Type that may be of use to other members.

A few weeks back I happened to come across a thread in this forum where a fellow S Type loony had found it necessary to replace a rear drive shaft because of a failed/busted ABS Reluctor ring. That exercise seemed to have been a bust for him at the time as he was still getting the ABS problem and frankly I was unable to offer him more than a little friendly support rather than a positive solution. Seemingly, and I'm sure it must be true with other marques, 'What goes around, comes around', and week or so after that exchange up popped the ABS/TCS warning light on Black Bess. This coincidence though was compounded by a further coincidence insofar that this ABS warning arrived simultaneously with the return of The First Lady and her new ride Red Bob. Some of you will know that I had a ABS failure on the very day that The First Lady came home from the dealership with Red Bob.

I won't labour these fateful events other than to grumble 'Why me?'

Anyway, out comes the newly acquired ODB2 reader which tells me its the Off Side Rear at fault and the controller is not getting a consistent wheel speed indication - which set the short hairs on end (given my earlier discussion on this site) and got me in a lather thinking I too may need to replace the drive shaft.

So, up goes the back end and off comes the wheel. Visual inspection reveals no apparent damage to the Reluctor Ring, its in the right position on the drive shaft and no significant debris blocking the slots. Thorough clean with the help of some DW40, wheel back on, code re-set and quick spin to check. Twenty metres down the road - ABS/TCS warning, b$%^%r!

Check this and other web sites for pointers - nada (other than drive shaft). Check Google, eBay et al for replacement Reluctor Ring - nada in the UK but oddly I could get them from the US. Check availability of replacement drive shaft - possible but not cheap and I have to be careful to get the right one.

Before making a commitment though I decided on one last try to remedy the problem without resorting to the wallet - always to be avoided if at all possible.

So, up goes the back end, off comes the wheel. This time though I went over the Reluctor Ring with a piece of emery cloth to remove any corrosion and I also went to what I thought was an extreme by using a small electrical screw-driver to scrape out and clean all the slots in the Reluctor Ring paying attention to remove any crusty bits of rust higher than the underside of the ring itself. Blow out all the debris Wipe down with some WD40 and make sure to clean around the Sensor Head - I should say I tried to remove the sensor to clean it thoroughly but was frustrated by a rounded bolt head - another job for the future. Wheel back on, car on the deck, code re-set, test drive - SUCCESS!

Short answer is that it was either dirt or debris around the sensor head that I did not get the first time or it was the crusty rust deposits in the ring slots that were culpable. Those of you that may encounter this problem in the future should try this solution first before getting your wallet out for a new drive shaft.

While I'm reporting this it may also be helpful to some to note the following:-

1. It seems two types of Reluctor Ring were fitted to the S Type rear end. One has rectangular slots  and the other has circular holes. It also seems that there are different diameters and different numbers of slots/holes.
   1. If you find yourself considering buying a replacement drive shaft you need to be careful to get the right one for your car.
2. During my search for possible solutions I came across some guy who was asking how to fit a RR tot he Drive Shaft and specifically if he could/should weld it into place.
   1. NO! The reluctor ring is not welded into position. It is pressed into place on the drive shaft and probably with the help of a little heat to expand the ring before its placed.
   2. Unless you have the kit to accurately press the replacement ring into place and can clean up the drive shaft head to a suitable standard do not be tempted to buy one of these.

To close - anyone had any experience of drilling out the ABS Sensor retaining bolt?

[piria33]

This is the window type. Quite a job getting the shaft out of the hub but once there and cv joint cleaned up the ring just needed heating up in the oven and with a slight tap it slipped on very nicely. Used a feeler guage just to make sure it lined up same as the old one bit it did also have a slight edge on the cv joint so it lined up perfectly.

Upgraded ring so will resist stretching much better.

[reis61]

hello christopher

What inner size did you buy from reluctorrings.com? I have the exact same problem as you and measured the diameter of CV joint and I come to 88.9mm. What type of motor and drive does your S-type have? I need to buy one from England in the Netherlands I can't find anything, would you please help me with this? awaiting your message. Thanks in advance

greetings  reis