Replacing front brake disc shields
 

I've got to replace the front shields on the Exxon Valdez (1997 940) as the old ones have more holes than metal.

Is the hub nut a 27mm or a 36mm one? I have seen both sizes quoted and want to make sure before starting the job that I have the correct socket.

The process itself looks straightforward:

jack up and support the front end;
remove the road wheel;
undo and secure the caliper;
remove the disc and hub nut;
apply heat/penetrating fluid/"industrial language"/cutting torch to the old backing plate;
clean up the mounting and apply sticking plaster/soothing balm to injuries;
fit new plate;
re-install disc, hub nut, caliper and road wheel, tightening as you go;
have another brew and biscuit/pastry of choice;
attend minor injuries clinic.

If anything is missing from the above please feel free to add it in.

I'm pretty sure it is a 36mm but it needs to be a thin walled socket as a normal thickness one doesn't fit inside the recess.

I had to change the front wheel bearings on mine a few years back and i'm fairly sure it was a 32mm nut holding the hub on. Might be wrong and it was a 36mm with the replacement being 32mm though. Fairly sure the replacement that came with the new hubs/bearings was a different size.

I think it'll be a case of "Suck it and see", i know on my other beast the OE nut is 32mm but aftermarket suppliers send a 36mm nut (same thread size as OE though) mostly although i've heard of 30mm nuts as well. That is on the driveshaft that goes through the hub and is torqued to ~315lbft, much higher than the Volvo! :err:

I therefore suspect there is one size on the Volvo that is the OE size but the nuts supplied with aftermarket bits may well be different.

As for your method statement, it sounds about right except for no mention of the pads - presumably dealt with alongside the caliper though.
That aside, a bit sparse on the application of Curses and Naughty Words and refreshments for my liking, i'd need much more of those in my method statement! :thumbs_up:

The front hub nuts on my 1992 940 are 36 mms. I had to buy a suitable socket. Not sure about the “thin wall” as mentioned by Luke.
They a VERY tight.
I managed to free the nearside one with a long breaker bar but could not move the offside one. Extending the breaker bar with a scaffolding pole threatened to snap the breaker bar or burst the socket. I took the car to my friendly local garage who loosened it with an impact wrench. Then I tightened it enough to drive the car home.
Take care when removing the hub as the bearings are a loose fit. Wrap your fingers around the back of the hub as you remove it to prevent the bearing dropping out.
The wire to the ABS sensor is located in a small bracket attached to the back plate. This will need to be removed and transferred to the new back plate. I think that it was originally secured with a very small nut and bolt which was so badly corroded it needed to be cut. I secured the bracket to the new back plate with a pop rivet.
I bought replacement hub nuts from my dealer ( VO 1387624 ) but refitted the old nuts with thread lock.
Haynes states torque is 100Nm plus 45 degrees.

99.9% certain its a 36mm socket as I bought one last year for my impact wrench. I also replaced the bolts holding the plate to the strut as they were completely knackered.

I can double check when I get home if you want ?

Just checked and it was 36mm. I just bought a standard 1/2 drive impact one and it fitted the recess fine

Just pop the cover off to check, you might even be able to do it without removing the wheel.

Make sure you have a good breaker bar, I just about managed with 0.6m, I struggled to get it fully tightened with the bar nearly breaking in the process. Probably 1m is needed and ideally 3/4" drive.

The bearing in later cars (ie yours) are integrated with hub, they won't fall out.

If you have high miles and are getting steering wobble under hard braking you might want to consider new hubs in the process. The bearings are not adjustable and when worn just become loose. Mine were gone at 170,000 miles but not detectable by the normal hand tests.

https://i.postimg.cc/CnhG5J21/strut.jpg

https://i.postimg.cc/D8YrfrPv/shield_2.jpg

A breeze to get off with an impact wrench. Angle tightening not quite as easy:regular_smile:

I used a 6ft scaffold pole on a 3/4 drive socket set to remove. Torque wrench and 1/2" drive to refit with 2' breaker bar to do the angle with a protractor although 45deg is fairly easy to guess.

New hubs including bearings can be scarily expensive, especially if they don't need doing yet.

Cost from Volvo for front hubs is 2x271644- £281.60. Wheel hubs a pair
2x6819759- £109.80. ABS RING TO PRESS ON HUBS. a pair

I replaced mine with SKF which were still £100.00 each

I decided to dump mine and not replace as they are not an mot fail if not fitted lol

Brake pads? You mean there should be pads in the calipers?

The use of industrial language is rationed, while refreshment breaks are frowned upon by the management as it means my coming into the kitchen and leaving muddy pawprints everywhere. Therefore it's one brew before starting the job and possibly a further one after the first side is finished.

You bought the abs ring separate? Gen ones come with them according to this pic:

https://www.ipdusa.com/products/8392...-271644-107901

Read more carefully Mr Bagster ! I didn't buy the Volvo ones. I bought SKF.

The Gen Volvo would be £196.70 each including ABS ring so the IPD ones at $276.00 Dollars inc ring is the same ( based on fluctuating exchange rates )

The SKF ones came with the ring and I bought direct from SKF at around £100.00 each

I did mine with the brakes last year.
It's fairly simple although an impact gun is useful as one of the backplate nuts on each side was siezed needing a bit of brutality and a new nut.....

the angle bracket holding the ABS sensor needs drilling off and riveting onto the new plate.

The hub nut is single use so a new pair will be needed.

I think I have a spare 36mm socket if you need one, I'll be in Great Barrow on Saturday if it's of use.

Tightening of nut from Vadis:

Tighten nut (use new nut)
Tighten until axial play has just disappeared, then tighten to DEFAULT-ENTITY 100 Nm (74ft.lbs.)&/emph;. Finally, tighten to 45°. Use protractor 951 2050

As you can see in the pic mine had all the strength of a lace (paper) doilly.

One thing to note, the backplates came from Brookhouse and were of decent quality although I found that the raised metal ring that acts as a dust shield around the centre was too deep and caused rubbing with the hub on first assembly.
I scribed a line around the inside of the ring with the dimension taken from the old backplate and trimmed them down with an angle grinder and flap disc, taking care to deburr and clean afterwards.

I have a suitable socket, but thank you for the offer. There appears to be more metal on your old backing plate than mine!

True, they take a bit of research to get decent priced ones that are not complete sh1t. Do not get anything the means "economy or regular" brand.. premium only (by "car parts for less" / ECP language).

Just wondered why you listed the abs ring number!

Did the SKF ones come with new hub nut and dust cap?

FRF listed the hubs that way.

SKF ones came with nut but I don't think they had dustcaps. I had ordered dust caps from FRF before starting the job and I'm pretty certain that was the ones I used

R.I.P. Plan A
 

Well, that didn't go according to plan, so maybe Herr von Moltke was correct about plans not surviving first contact with the enemy.

Jacked up the front end and removed the roadwheel on the driver's side as there's more room there. So far, so good. Thereafter, not so much.

Step 1. Inspected the bolts that hold the caliper to the yoke - not so good as the upper one was rounded; a cold chisel and a BIG hammer looks like the solution to this problem and I haven't got a suitable chisel at the moment.

Step 2. Then assessed the Socket-cap bolts that hold the caliper carier to the strut; more bad news as one of the heads is rounded.

Step 3. Took a small chisel and a hammer to the remnants of the old backing plate and removed the majority of it. It is now in the bin.

Re-fitted the roadwheel and turned the car around to do the nearside. See Steps 1 and 2 above for the outcome.

Refitted the roadwheel, put the tools away and had a brew.

On the positive side, there was no use of industrial language and a trip to A&E was not made.

Oh bugger, still the good news is you can come to the meet tomorrow in it as it isn't in bits :D

Two steps forward and three back then? :thinking:

If those bolt heads and nuts are in such poor condition I suggest that you invest in a set of 1/2” drive twist sockets. I bought a set a couple of years ago after having some demonstrated to me by a neighbour who owns a small garage. Assuming that you have the correct size twist socket for the offending bolt they haven’t been beaten yet. Good luck.

They were like that on my breaker car. I had to go for tons of heat followed by hammering a slightly smaller 12 point socket over the bolt head. I then let the impact wrench do the biz :teeth_smile:

That’s how the twist sockets work. Hammer on the appropriate sized one.

That would be these wee beasties then Ian?

https://www.ebay.co.uk/itm/174920246201

Often thought about a set but so far haven't got to the point of actually needing them.

I also keep thinking of an induction heater for reluctant nuts, at the moment they're a bit on the £OUCH! side for my pocket Vs the amount of use it would get. Been seriously looking at building my own which would cost a few quid and work off 12V but again, how often would i use it?

*** EDIT *** This is the sort of animal i mean but the dcimal point is in the wrong place!

https://www.ebay.co.uk/itm/184705382512

The beauty of it being flameless is the surrounding areas don't get fried, the heat is concentrated inside the coil and heats the nut more than the thread it's on. Oh yeah and less chance of burning through a rubber fuel or brake hose! :err:

Yes that’s them.
That induction heater looks clever, but a lot of money for something hardly ever needed. Ideal if a business though where time is money.

I've heard these are very good https://www.amazon.co.uk/Irwin-Bolt-...c=1&th=1&psc=1

I think Luke recommended them to me

More like one forward and 4 back.

After ordering and recieving both a set of Laser Socket Cap removal bits, and a set of twist bits I returned to the fray this morning, tackling the nearside set-up as it's easier to access when the car's parked in its usual spot.

Jack up, remove wheel, prop up on axle stand - all ticks.

Undo bolts for caliper slides, with no need for twist bits - ticks.

Remove pads and put caliper out of harm's way - ticks.

Remove caliper yoke bolts - pass the Laser bits please. Application of breaker bar to socket and the yoke bolts budged - more ticks.

Remove hub cover - pardon? How do you remove the hub cover without destroying it?

Put the brake system back together; I KNOW the yoke and slide bolts are use-once items but the Valdez is going nowhere and I'd rather have it on 4 paws than three paws and an axle stand.

https://blog.fcpeuro.com/how-to-repl...on-a-volvo-940

You can buy new from the dealer but they do straighten out if you crease them too much

Good to hear you made some good progress - for hub cover i'm assuming you mean the dust cap that simply levers out from the centre with a large flat screwdriver or similar - alternatively a few delicate taps around the circumference of the dust cap with a screwdriver/chisel/punch away from the hub usually shifts it.

*** EDIT *** Mark beat me to it and included pretty pictures to show the same as i was saying. :thumbs_up:



Slide bolts i believe are reusable, yoke bolts are only single-use only because they are patch bolts. Clean the threads of the old thread locking compound, refit both so the caliper is secure then remove one at a time, add a few drops of Threadlock (i use Loctite 243) then refit to the recommended torque (100Nm/74lbft rings a bell but would have to check), move on to the other once the first is tight and the caliper won't move and repeat, job done.

"Hub cover" is the dust cap; I now need to get out the robbery kit and buy the yoke bolts, backing plate bolts, caliper bolts and a replacement spigot bolt - the one that keeps the rotor and hub together as I watched the old one disappear before my eyes. Unless someone has a spare they no longer need?

I might have one kicking around. I can see when i get in. I might also have some dust caps and some nice shiny bolts for the backing plates

Realised yoke bolts are caliper carrier bolts ! 10mm allen key head

Appreciate your looking. If you have them I'll take them off your hands.

I thought about applying violence to the dust cover but my neighbour's on a 2am start and wouldn't appreciate the noise of an impact generator.

just double checking that it's one of these that you need https://www.skandix.de/en/spare-part...screw/1013799/

That's the very item; but 12 Euros for a single screw strikes me as slightly extortionate. If I knew the thread pitch I could probably buy something suitable off the shelf for a small fraction of that!

Even more extortionate when I learn that the caliper yoke bolts are 3.60 Euros each.

I wonder what Volvo would charge for the real thing? :thinking:

Probably cheaper from FRF with VOC discount

I'm waiting for Clive Brook to get back to me with prices.