ABS ring repair

[fla 9]

Basically, how to do and what to look for. Pics would be useful.

 

Thanks all.

[Supercharged 2]

Errr... do you mean the rotors?? - front or rear?

[2cc 0]

fla - Just got you a pic of the front rotor as I have a hub off the car, but am at work and can't post it till I get home later. I'm planning to do some work on the beast tomorrow & will take some pix of the rear but can't post em till I get home later tomorrow night if that'll help. The rears you have to take the disc off, the rotors are a push fit in the rear of it; fronts again its fitted on the inner side of the disc, but iirc you have to pull the hub apart to get at it, its definitely not fitted to the disc tho', I've changed loads of those.

[2cc 0]

fla Guessing you haven't done this before so here you go, photo of the front abs rotor. You can see it between the disc back plate and the drive shaft, its the thing with all the square holes in it. As I said, I'm pretty sure you have to remove the brake caliper and carrier, the disc, and then the big nut (its torqued up real tight but can't recall the figure) on the end of the drive shaft to remove the flange. IIRC the rotor clips on to the back of it, pretty obvious when it's in bits. Reverse process to rebuild and torque the nut to the right figure - dealer could tell you if someone on here doesn't.

On the rear its a similar task, remove the caliper and carrier - you'll need a hex drive tool to remove the fixing bolts, Halfords or any tool shop do one with a 1/2 inch socket drive. Then remove the grease cap from the centre of the disc, undo the nut and pull the disc off the stub axle. The abs rotor clips into the back of the disc & can be pried off carefully with screwdriver if intend to reuse, or just rip off and fit new one - just a push fit. Make sure you don't get rust & crap in the axle grease & refitting is, as they say, the reverse procedure. Do the nut up till disc hard to turn then back off till the spacer washer behind it can be moved 'relatively easily' side to side with a screwdriver as lever. This is one of those feely things that you get used to with experience but you don't want it too tight or you'll knacker the bearing when driving it. Too loose, and you will be able to feel the bearing rock after fitting the wheel and waggling it side to side (or top to bottom). Good idea to check this before you put the split pin in. HTH.

[fla 9]

2cc, many thanks bud. I'll have a bash (not literally!) this weekend and see if the rings are okay. Which other tools will I need as I dont want to get stuck in the middle with the wrong size sockets and allen keys!

[2cc 0]

Hi fla, sorry didn't get round to posting pix of the rears but actually you can't see them till you pull the disc off cos the backplate covers em completely. Just a shame to have to strip it all just to check em. Pretty standard tools, 13, 15 (open), 17 mm, 8mm hex drive tool - comes with a 1/2 inch drive for a t-bar - don't try and use an allen key cos these take some serious undoing and need some proper leverage, 22 mm skt (I think) for rear hub & some new split pins, 30 mm skt for front hub nut & you'll need new ones as they are one off use jobbies but sorry can't tell you what to torque em up to, also suggest get new bolts (4) for the rear caliper carriers as they get pretty manky, a large cross head screwdriver for the front disc set screws & that's about it I reckon. I use a hammer to get the rear hub dust caps off, just tap it gently on the side (you can get just slightly behind it) and keep rotating it and it will ease out as you go. It's all pretty obvious when you strip it down. I didn't say before, but been said on similar threads, to recheck the rear brgs for play after about a week when they'll have bedded in. Have fun, I'll be away till sun night/mon so will look then to see how you got on.

[h100vw 0]

24mm socket for the nut. :)

[fla 9]

Thanks again Chris. Looks like a busy Sunday, and if I need some bits itmight be off the road for ANOTHER week... :x

[stevemac 0]

24mm socket for the nut. :)

Tightening torque setting = as tight as you can with a 2ft breaker bar.

[fla 9]

Had a little look at the rotors, without taking the discs and calipers off but there were no visible cracks. I've just put the error codes into Bentley (should have done this before of course!). The report is as follows:

 

VAGCOM:

ABS Wheel Speed Sensor: Front Right (G45)

04-00 - Mechanical Malfunction

(also for rear left and rear right wheels)

 

Bentley:

Excessive or insufficient gap between speed sensor and pulse wheel (signal not OK)

 

Whilst 2CC has given some useful info, I want to avoid taking everything apart if I can get away with something simple like removal and cleaning of the sensors. If that IS the case, how do you remove the sensors?

[stevemac 0]

Removing the front sensors (without damaging them) can be extremely difficult. I had to burn mine out with a blowtorch. They were absoloutely solid & refused to come out by other methods.

 

The problem with the front sensors is that they are mounted into bare metal (hub carier). This bare metal rusts inside the hole around the sensor, causing it to expand & squeeze the sensor very tightly. To re-fit the new ones, I had to drill-out the hole slightly so that I could get them in.

 

Haven't done the rears so I'm not sure if they'll be subject to the same problem.

[fla 9]

Thanks for that Steve. I presume removal is the only way to clean them then? Based on VAGCOM and Bentley what would your diagnosis of the problem be?

[Heardy 0]

It sounds like one ring's will be bent .I've seen them damaged before when wheel bearing's have been fitted. When did the light start coming on?Is it since you carried out some work on it?

[stevemac 0]

fla, Best way to clean them is with a can of brake cleaner. It comes in an aerosol - you just spray it on & it disolves the dirt.

[fla 9]

Simple enough I guess. Strangely the ABS light comes on initially (as usual) but then extinguishes after the 10 second period indicating no problem with the ABS.