Front brake disc back plates

[940volvoman]

How critical are the disc brake protector back plates?I'm going to have the brakes looked at on Monday and wondered if it's worth getting the front ones replaced which have rotted away..?

[360beast]

I've seen plenty of Volvo's running no backing plates so don't worry about it. It isn't an easy job to replace them if the bolts are rusted and round off easily.

[RollingThunder]

I don't think there is a legal requirement for them (but I may be wrong), however the backing plates act as shields for the discs, stopping oily debris getting onto them, and hence onto the pads. Personally, I'd replace them if I could. The plates themselves are not that expensive and pattern parts would be fine of course.

Having said that, as 360beast says, the bolts tend to get crusty and it could turn into quite a mission to replace them

[Ian21401]

To the best of my knowledge, as previously stated, they are not required for MOT but do help protect the disc.
I replaced both of mine some time ago. It requires removal of the brake caliper, caliper bracket, brake disc and front wheel hub.
There is a small bracket for the ABS sensor wiring attached to the back plate. This is not fitted on the replacement back plate so it will need to be transferred. If your lucky it may be possible to loosen the small nut and bolt which secure that bracket to the back plate, but mine were beyond redemption so I cut the bolt and used a pop rivet to secure the bracket to the new back plate.
The back plates themselves are secured by small flange screws. (three each side I think). I did the nearside first and found that the backplate was secured by three female head hex key head screws, the hex sockets of which of which simply rounded so I had to cut them out and renew them upon reassembly. When I did the offside I found that it was secured by three hex head flange screws which I was able to remove and reuse. No idea why they were different on each side.

[940volvoman]

Thanks,Ian 214101

How difficult is removing the hub? It isn't something I've ventured near before....

[Ian21401]

Note that this relates to my 1992 940.

Front hub nut VO1387624. ( 36 mms I think.)
Brake back plate VO9140760. For either side as they are not handed.

Once everything else is removed the large hug nut needs to be removed then the hub can be removed from the stub axle.
Care is required when actually sliding the hub off the stub axle as on some models, including mine, the bearings are a loose fit in the hub races and can be dislodged if not held in place by your fingers whilst actually sliding the hub off. Especially the inner one. If they are a loose fit try to ensure that they do not fall out of the hub.
The hub nuts are VERY tight. (100Nm then angle tightened 45 degrees.)
I managed to free the nearside one using a 2ft. breaker bar and jarring it with a lump hammer. I could not free the offside one and needed to enlist the help of a friendly local garage with an impact wrench. If yours is being done by a garage they probably have impact wrenches.
It is suggested that new nuts should be used every time but, even though I had invested in new nuts, for some reason I reused the old nuts using thread lock.
I’ll try to find other related threads and insert them here.

https://www.volvoforums.org.uk/showt...ront+wheel+hub

https://www.volvoforums.org.uk/showt...ront+wheel+hub

https://www.volvoforums.org.uk/showt...ront+wheel+hub

I hope this helps.

[baggy798]

Can confirm they are not needed for the MOT, but needed access to bash the ABS sensors out so replaced them as well. The bolts holding them were caked in rust and I thought they were 15mm at first but they turned out to be 12mm. Sprayed liquid wrench both sides, banged them with a hammer on the heads to try and shock them a bit, and got a 6 point socket on very securely and they all came out. I replaced them with M8x14 stainless hex bolts.

The bracket for the ABS wire is still available, about £8.50 each. They are originally riveted but I used an m5x10 bolt and locknut.

Yeah, the hub nuts are very tight, I couldn't have loosened or angle tightened them without a beastly impact wrench.

[J liddy]

I've done that job will post my experience of it shortly

[TonyS9]

Removing and correctly retorquing the hub nuts is hard. I have a 0.6m 0.5" breaker bar couldn't quite do it, but I um... made do with whatever I could achieve. Really needs a 3/4" 1.5-2M breaker.

[griston64]

The hub nuts are 100nm then 45deg angle tighten. Not that difficult

I had to use my impact wrench to remove though