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Discussion Starter · #1 · (Edited)
This is NOT a 'How To' more of a 'How not To'.

Had ABS dash warnings, Traction control and Tire pressure warnings come on. I scanned with vcds and fault with rear LH wheel speed sensor found. Vcds fault was sensor faulty 'Mechanical'. That's a clue because after fault clearing there was no fault at key on so the sensor electronics were o.k which leaves the magnetics.

ABS sensors are fitted behind each wheel bearing and pick up magnetized segments on a ring attached to the back of the bearing. A 'mechanical' fault could be damaged magnet segments on the wheel bearing, increased clearance due to a worn bearing or a bad sensor head. A common fault on VAGs is rust builds up behind the bearing hub, falls into the ABS sensor gap and chews up the sensor head and/or the magnetic ring on the bearing. In my case there was a large amount of rust and the sensor head and ring were both damaged.


In view of the age of MY07 I decided to replace both rear wheel hubs and ABS sensors which also gave a good opportunity to check the rotors. I had already replaced rusted and seized calipers. V.W have used TWO sizes of rear axle bearings 30mm and 32mm and you need to determine which you have before ordering a rear hub repair kit. You can only be sure by removing the hub and measuring the stub axle diameter.

Removing a rear hub and bearings

There are two methods. The first is to remove the calipers, rotor/disc & retaining screw then wiggle off the rotor to expose the hub center cap and hub bolt. Garages with 4 post lifts will remove two M14 spline Torx retaining the caliper back plate and lift the whole lot away from the hub. This is the fastest method but comes at a price. Pads and calipers will have been changed frequently and their bolts should undo easily. The M14 caliper support plate bolts may never have been removed and are torqued to 200Nm. This requires a long torque wrench and is easy to use when the car is on a lift with no obstruction below the wheel. I used this method after jacking one side on the side jack points. I think the first method would have been easier. There is a lot of suspension clutter and access to the rear bolts needs at least one 100mm socket extension.

To remove a rear hub complete with bearings you have to remove a T17 (12point) bolt with a large mushroom head. This is fastened to a torque of 200nm plus 1/2 a turn. I needed to remove the hub by fair means or foul to measure the bearings. My rotor removed in the first stage was in poor condition. The outside part you (and testers) can easily see looked o.k. But the inner face and hub, hidden by the brake back plate, was a rusty pitted mess.

Removing the large T17 hub holding bolt:

There are many YT videos for this. Most are wrong and many will not show you how to tighten the bolt to 200Nm torque+ 1/2 Turn and what tools you need.

The hub bolt is a T17 12 point spline Torx. Warning: Most spline tool sets only go to T16. If you use a T16 you will damage the bolt and socket!
Tried the following:
1. 1/2" hardened impact T17 socket and a 1/2" 3ft breaker bar: Bar bends about 9 inches, nothing moves and the breaker bar hinge joint will break.
2. As above using an electric impact driver set for max torque of 340Nm. Nothing moved.
3. 1/2" socket, 3ft breaker bar, propane gas flame on the bolt head: Nothing moved, too much metal heated.
4. As above, 120 Amp electric arc via a tungsten rod on the bolt head: Nothing moved.
5. Oxy Acetylene, Oxy propane: I don't have that.
6. Hammering the hub: Doesn't work and if you hit the center spline bolt your socket won't fit any more!
At this stage I will insert the following important note:

"If you cannot remove a hub bolt with your garage tools, then you will not be able to tighten it to V.W spec."

Do not think this bolt is just 'stuck'. The large mushroom head holds a lot of friction after the bolt has been stretched 1/2 a turn. V.W put some blue thread lock on the bolt, but IMHO it contributes little to the stubborness. My action plan was to get the bolt off by any means even destructively, measure the stub axle and order new hub kits. Then think about what garage tools are necessary to tighten the new bolt and remove the bolt from the RH hub. My destructive approach was to cut the raised ring on the hub around the bolt to allow deeper penetration for a 120mm angle grinder cutting disc. Then make 4 cuts across the head of the bolt away from the strong center and remove the bolt whilst still hot from cutting.

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That worked and the bolt and hub were free to come off and trashed. Next check the axle size:

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32mm diameter, so order a pair of rear hubs, ABS sensors, rotors and move to the RH side.

Hub Bolt removal tools:

1/2" socket tools are ubiquitous on Ebay. Those and long 1/2" breaker bars will not work! You have to move up to 3/4" square (or 1 inch) and the T17 spline socket MUST be tough chrome vanadium. There are plenty of 1/2" hinges sold as replacements for broken breaker bars. The problem isn't the socket, but how it attaches to a LONG breaker bar. I persevered with a 1/2" socket to the extent I fixed a short length of 1/2" key steel into a long length of 10mm flat steel bar. I could achieve the 200Nm starting torque but at 10 degrees turn, the key steel twisted like a helter skelter!

Of the manyYouTube vids that don't show tightening or pro garages using hammers and Oxy acetylene, this one shows what is actually required:

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The problem is achieving the extra 1/2 turn stretch super torque, I decided the solution must use a simple a 3/4" Tee bar, no hinge, no ratchet and a long breaker bar. I have an Elora 3/4" tee bar and plenty of long lengths of 2" OD ali scaffold tube. I made 3 X 30mm wide spacer collars to slip over the 20mm dia. chrome vanad. tee bar that would fit nicely inside ali scaffold tube:

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I ended up with this:

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You can see I am removing the RH side bolt, no grinders, saws or heat. The bar is pulled down in a series of short jerks as the bolt undoes and tightening is a dream. I wrapped some cloth around the tube to protect the paintwork. In future I would use a 100mm 3/4" extension on the socket. Note: Most torque wrenches max out at 150Nm. I have a long 330Nm Norbar torque wrench to set the initial 200Nm bolt torque.

Testing your work:

Bad things can happen. You can start on the wrong wheel, the new hub & bearing kit you bought had no protection over the magnetic ring and segments are invisibly damaged, you levered behind the new ring and damaged it. You don't want to find this out after tightening the 'use once' hub bolt. Fire up your diagnostics and go to ABS module 03 Advanced Measurements. There you will find a list of wheels and sensor outputs in mph. Before you start , rotate the suspect ABS whel by hand and check there is zero speed output. disconnect the ABS sensor, erase faults and rescan. Diagnostics should confirm the wheel sensor you removed is the same as the one it previously showed as faulty. Reconnect the sensor after replacing it. After fitting the new hub kit, Tighten the hub nut to about 50Nm, rotate it and check for a speed output from the sensor. Note: This isn't a foolproof test because if one magnetic segmet in the bearing is damaged, you only find out when all 4 wheels are rolling on the road.

Now tighten the bolt to the specified torque + 1/2 Turn, fit the cover cap and caliper bracket. if you have removed both T14 spline bolts from the rear, carefully clean the splines with a sharp tool, replace the bolts and tighten them to spec. torque (200Nm ?).

Gotcha!

During this work vcds gave a steering angle control module fault. This wasn't there initially and came on either during a battery disconnect/re-connect, or when I removed an ABS sensor to check the correct wheel. It's rather worrying because removing the steering wheel, clock spring and a load of electronic modules to get to the steering angle controller is a LOT of work. Something tripped in memory that in vcds I spotted small print text 'init'. Now I know that rolling down the road is supposed to re-calibrate the steering modules and put out the warning, but vcds said the controller was actually faulty. I checked its output whilst turning the steering and it stayed at 0 degrees. Here's my theory: The steering angle module stores previous settings. These are lost when the battery is disconnected but when an ABS wheel sensor is disconnected and key on, the steering angle controller clears its initialisation data and remains locked out until the ABS fault is cleared first. After replacing the rear wheel hubs and ABS sensors, the phantom steering angle controller fault cleared - Phew.

Sourcing EOS rear wheel bearing kits and sensors:

There are a zillion of these on Ebay priced from £20 to £80. Mine was from Napa and boxed but still questionable aftermarket quality. I noted there was no bearing number visible on the bearing (it could have been on the inside? ). The V.W OE bearing is 'Eff A Gee' number 805409B Z13. The price you pay for these kits depends on the quality of the bearings they used. Both 'Eff A Gee' and SKF manufacture V.W hub bearing kits using their bearings. If you want top quality and provenance, search for the bearing number and their kits will come up.

ABS wheel sensors are pretty simple electronically and there are plenty of Chinese substitutes. They are all ABS bodies. It is best to push the old sensor through after removing the hub, then clean around the hole. You can carefully prise them out from behind if you bend a small turn of a screwdrive to gently lever them out. I found it impossible to release the electrical connector until i had removed the sensor with its connector and lead still attached.

ABS Dash Warnings:

Never regard an ABS warning as an irritating sensor problem. Your wheel hubs are secured by one bolt and it's only torque that holds them there. Unlike the old way of using a castellated nut and cotter pin. If a bearing wears or your hub bolt works loose the ABS sensor gap will increase and change as the wheel rotates. This will put on the ABS dash warning until excentric rotation of the wheel permanently damages the ABS sensor and magnetic ring.
 

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Hi Vox

Mega write up. Need a few days to digest in detail ... . Like the extension bar solution.

Did you use axle stands as well as a jack ( sorry not read the full post in detail yet ...)..

It seems that if you use a large jack you can't use the sill axle stand point . Will try and get a pic to show what I mean

Regards



Sent from my SM-A526B using Tapatalk
 

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Discussion Starter · #3 · (Edited)
You MUST use axle stands or a secondary screw jack with any hydraulic jack. I've got a couple I've replaced seals on twice now because they will sag when left. You learn your lesson after removing a wheel, leaving the car on a hydraulic jack and finding it sat on the rotor next morning with crunched bodywork!!

This is my side jacking method, I don't do it a lot but for wheel bearings and suspension where you need space it may be the only alternative to a 4 post lift. For the front I cut a length of 9 X 2 board that fits across the sub frame and can lift in the center.

For side jacking I use a trolley jack and axle stand together. The trolley jack needs a short length of 3X3 or 4X4 hardwood with a 'V' groove cut in the top to sit across the jack cup. The axle stand has a similar smaller section of hardwood cut with a 'V' groove. You can practice with a wood saw on blocks to get the weIded cill seam fitting nicely on top of the block but NOT resting on the hollow cill itself. I jack under the cill seam as far forwards as I can, then slide in the axle stand just behind the trolley jack so its 'V' groove aligns with the cill seam, I have 2 axle stands so I could repeat for the opposite side, but I'd usually use ramps to get both wheels off the ground. Invariably after a few hours, the car will have settled on the axle stand NOT the hydraulic jack. Even with a big trolley jack and axle stand behind it, there is plenty of room inside the wheel arch to work on brakes and wheel bearings.

23550


AVOID thinking you can jack the rear in other places. As the suspension jacks up on the springs, the supporting jack point tends to 'roll' and you can end up with the rear end on top of you!

I've just discovered on Fleabay you can buy solid rubber inserts for jack cups and axle stands and I've just ordered some to try that are pre-cut to locate in the cill seam of V.Ws, 8-10mm slot size I think?

Stay safe, jacking up these modern cars in the wrong place can be risky to the car and yourself. I will warn you that when locating the cill seam to align with the 'V' cut block, always check and recheck that's where the jack is lifting because in poor light it's easy to misalign and if you jack under the cill it will fold inwards.
 

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You MUST use axle stands or a secondary screw jack with any hydraulic jack. I've got a couple I've replaced seals on twice now because they will sag when left. You learn your lesson after removing a wheel, leaving the car on a hydraulic jack and finding it sat on the rotor next morning with crunched bodywork!!

This is my side jacking method, I don't do it a lot but for wheel bearings and suspension where you need space it may be the only alternative to a 4 post lift. For the front I cut a length of 9 X 2 board that fits across the sub frame and can lift in the center.

For side jacking I use a trolley jack and axle stand together. The trolley jack needs a short length of 3X3 or 4X4 hardwood with a 'V' groove cut in the top to sit across the jack cup. The axle stand has a similar smaller section of hardwood cut with a 'V' groove. You can practice with a wood saw on blocks to get the weIded cill seam fitting nicely on top of the block but NOT resting on the hollow cill itself. I jack under the cill seam as far forwards as I can, then slide in the axle stand just behind the trolley jack so its 'V' groove aligns with the cill seam, I have 2 axle stands so I could repeat for the opposite side, but I'd usually use ramps to get both wheels off the ground. Invariably after a few hours, the car will have settled on the axle stand NOT the hydraulic jack. Even with a big trolley jack and axle stand behind it, there is plenty of room inside the wheel arch to work on brakes and wheel bearings.

View attachment 23550

AVOID thinking you can jack the rear in other places. As the suspension jacks up on the springs, the supporting jack point tends to 'roll' and you can end up with the rear end on top of you!

I've just discovered on Fleabay you can buy solid rubber inserts for jack cups and axle stands and I've just ordered some to try that are pre-cut to locate in the cill seam of V.Ws, 8-10mm slot size I think?

Stay safe, jacking up these modern cars in the wrong place can be risky to the car and yourself. I will warn you that when locating the cill seam to align with the 'V' cut block, always check and recheck that's where the jack is lifting because in poor light it's easy to misalign and if you jack under the cill it will fold inwards.
Hi Vox,

I think I see what you mean . I have purchased a few Jack pad options recently , I will dig out a few pics to show what I've got . I seem to have the same problem as in if i use the area on the sill marked for jacking my Jack takes up a lot of space so i can't fit my axle stand in the same area. It a bit difficult to describe what I mean so hopefully the pics will make a bit more sense

Regards
 

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Discussion Starter · #5 ·
The rears are less worry because there is less weight on the cill jack points - until you start pulling the hub bolt down 1/2 turn. I locate the obscure arrows they put on the cill, then position my wood/rubber 'V' block just forwards of it towards the wheel for the hydraulic jack. My jack has a V. large 145mm dia. cup. I can then get the axle stand right close to the hydraulic jack and lower the car on the stand. I only work under cars when they are on stands, ramps or trapezoidal screw jacks. After making the ramps I welded up a small steel box frame from left over 1" angle and set in some 1" plywood. This is a useful raised support I can sit a screw jack on to work with both wheels on ramps and remove a wheel. A 4 post garage lift with space to use it was always a dream, but I'm getting too old to consider that now.

I received two slotted rubber pads for my old halfrauds axle stands this morning. They were a reasonable fit on the stands, but I shaved their angle a little with the bench grinder to get a perfect fit on the side 'wings'. Hardwood 'V' blocks still work well though.
 

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The rears are less worry because there is less weight on the cill jack points - until you start pulling the hub bolt down 1/2 turn. I locate the obscure arrows they put on the cill, then position my wood/rubber 'V' block just forwards of it towards the wheel for the hydraulic jack. My jack has a V. large 145mm dia. cup. I can then get the axle stand right close to the hydraulic jack and lower the car on the stand. I only work under cars when they are on stands, ramps or trapezoidal screw jacks. After making the ramps I welded up a small steel box frame from left over 1" angle and set in some 1" plywood. This is a useful raised support I can sit a screw jack on to work with both wheels on ramps and remove a wheel. A 4 post garage lift with space to use it was always a dream, but I'm getting too old to consider that now.

I received two slotted rubber pads for my old halfrauds axle stands this morning. They were a reasonable fit on the stands, but I shaved their angle a little with the bench grinder to get a perfect fit on the side 'wings'. Hardwood 'V' blocks still work well though.
Hi Vox
See attched pics . One kit ( 3 part kit) is from PSI tuning and using the 4 post lift jack points . a few comments on the web re stuff being crushed but i find it works well. However it blocks axle stand access due to its location . the second (single part) is from power flex for a mk5 golf and fits the sill area fine , just enough room for a axle stand
 

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