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[addy]

Could anyone tell me, before I undo them. If the four female Torx Head bolts, allow the back plate dust shield, to move?  The reason I am asking is that, I am completely rebuilding the handbrake on the wifes 1995 Omega. The pins that are on it to hold the shoes, are the old type that twisted into the backing plate. The new ones come through the backing plate. I have read the modification Vauxhall did from the old style to the way the later style. Just want to confirm everything.  The Torx bolts I am on about can be seen, on the back plate and the new pin setup in the hub bearing guide.



Thanks in advance for any help.
Addy

[Nick W]

If you've tried a Torx bit in those bolts, then you've rounded them out. Especially if they've never been undone before.




They aren't Torx, but an earlier 12 spline bolt. For some reason. I think they're the only spline drive bolts on the whole car. oppsing Germans   The bit in my set for these is marked M10, but I don't know what that means as the bolts are M8... oppsing Germans




What are you hoping to achieve changing the pins, as the later style aren't particularly well located in the holes and you can't put a finger on the back to steady them. Fitting the springs can be interesting with the hub in place. ALWAYS assemble the handbrake before you fit the hub. This whole driveshaft/drive flange/hub/handbrake arrangement is way more complicated than it needs to be and is nuisance to work on. oppsing Germans

[Andy H]

When the keyholes in the backplates on my 1994 Omega became too rusty for the retainers to get a grip I bought a set of early Passat (that what it said on the packet anyway) retainers.

I was able to insert them from behind in the same way as the later Omega retainers. I didn't need to pull the backplates off. Don't know if the Passat retainers are different to the Omega ones

[GastronomicKleptomaniac]

Ive never done it, but can you not work on it in situ, cut the old pins off and drill it through (assuming the new ones mount in the same spot) rather than risking getting three bolts out and one that will round?

I do have a multispline bit set you're welcome to borrow

[addy]

Andy H.

This is what has happened to the pin retaining holes. So wanted to do the same as you had done. I can get to the one hole, but cannot see the other, will have another look in a while.

Hi Nick W. Thank you for the advice. I haven't touched the bolts, wanted to check before touching them first.

Thanks for all the help.

[Andy H]

It is definitely doable. I was convinced it wouldn't work but by persevering I was able to wriggle the awkward retainer in from behind.
You need to do it by touch, if you try to see where the hole is you will get an eye full of crap.

I may have distorted the hole a little (& flattened it again after) to get the retainer in but it was so long ago that I can't remember whether I had to go that far.

[Nick W]

Andy H.

This is what has happened to the pin retaining holes. So wanted to do the same as you had done. I can get to the one hole, but cannot see the other, will have another look in a while.

Hi Nick W. Thank you for the advice. I haven't touched the bolts, wanted to check before touching them first.

Thanks for all the help.

You could fix it in no time without removing the plate:


Drill or Dremel the holes a bit bigger
Buy some new pins
Fit them through some appropriately sized repair washers
Weld the washers to the back plate. You could probably epoxy them in place if you don't mind it taking a little longer.
Reassemble the handbrake shoes.

[Enceladus]

We repaired a '96 car in a similar manner to Nick W's suggestion. One of the pins had pulled through the backplate and damaged the locking slot. We used the slotted cap washer from a new pin as the repair washer, tack welded to the backplate, so the pin could still be inserted from the outboard side.

The bolts have female M10 XZN heads. XZN is also called 'triple square'. It's not Torx. Normally you need an extra long bit to reach through the hole in the hub flange. Looks like you have removed your hub, so have better access.

The backplate itself doesn't have to be completely removed, just moved outboard enough to allow the revised pins to be inserted from the inboard side. That's what you are supposed to do if the hub was still present.

Be careful with your backplates. They're scarcer than rocking horse dung.

[Doctor Gollum]

That picture is from the rear bearing change guide

[addy]

That picture is from the rear bearing change guide

You are correct. I borrowed it to show the bolts I was on about. I have had another look, I cannot seem to find anyway to put the pin in from the back. But it doesn't matter at the moment.

Now got another problem. The newer style fixing pins are longer than the original ones, that just twisted into the back plate. Also the new spring that fits on the pin, is wider than the original. This is causing the shoes to not fit correct.  The ones I need apparently fit the SENATOR, ROYALE, CARLTON and OMEGA, plus some old Vectras.

Thanks for all the help.
Addy

Thanks for any help. Addy

[Enceladus]

I believe you need Mintex fitting kit MBA667 or equivalent. The kit used on Carlton and Senator and others. See here.

Trouble is to get an original kit as opposed to the supersession kit which I think is Mintex MBA711. The picture in the link for the kit looks to be the correct kit, albeit some other make.

Or buy a long M10 XZN bit and see can you loosen the backplate bolts? If you can then the new pins will fit in from the inboard side.

[Nick W]

Now got another problem. The newer style fixing pins are longer than the original ones, that just twisted into the back plate. Also the new spring that fits on the pin, is wider than the original. This is causing the shoes to not fit correct.  The ones I need apparently fit the SENATOR, ROYALE, CARLTON and OMEGA, plus some old Vectras.

What does the spring is wider mean? Is it longer(which is what I think you mean), larger diameter coils, or larger diameter wire?


If it's too long, cut it down. I doubt it's a bigger diameter, but if it is you need the matching cap.


All these springs do is gently hold the shoes against the backplate so they can't move towards the hub and rub/catch on something. as long as that's happening, it's all good.




Triple Squares - I knew there was a correct term for 'spline drive bolt'

[LC0112G]

I've never managed to get all 4 of those bolts out without mullah-ing at least one of them. The spline head is made of something softer than cheese and rounds off very easily. I then end up angle grinding a slot in the head and then chiseling it round, which obviously means you need some more bolts for re-fitting. Not actually sheared a head off yet, but it's always a worry.

The new style pins, springs and cup washers do fit old Carltons/Senators etc without modifications, so I'm not sure why you can't get them to work on your car. They are a real faff though - one of those things where you really need 3 hands. AFAIKR unlike what others are saying I think you do have to get the backing plate off/loose first to get the new pin in from the back. Or I suppose you could prize the old slot open enough to get the head of the new pin in and then hammer/weld/glue it back in again. Not something I'd do, but....

[LC0112G]

Now got another problem. The newer style fixing pins are longer than the original ones, that just twisted into the back plate. Also the new spring that fits on the pin, is wider than the original. This is causing the shoes to not fit correct.  The ones I need apparently fit the SENATOR, ROYALE, CARLTON and OMEGA, plus some old Vectras.

What does the spring is wider mean? Is it longer(which is what I think you mean), larger diameter coils, or larger diameter wire?


If it's too long, cut it down. I doubt it's a bigger diameter, but if it is you need the matching cap.


All these springs do is gently hold the shoes against the backplate so they can't move towards the hub and rub/catch on something. as long as that's happening, it's all good.




Triple Squares - I knew there was a correct term for 'spline drive bolt'

From memory, the new style springs are a larger diameter (getting on for double), similar length, but much thinner wire diameter (perhaps half). They have to be wider diameter for the outboard end to sit in the flangy bit of the cup retainer thingy.

[polilara]

Is it so that new back plates are not available anymore. I remember that I read somewhere that "new production plates" could be found. If hub is away and you can open the four bolts I would install new plate...

[cam.in.head]

New plates seem to be readily available (albeit pattern) and they all seem to be the earlier style. As on carltons,calibra etc. (Pin from front)not seen any of the later type for sale ?
Don't know if they are 100% interchangeable ?
They are prone to rusting especially around the cable return Spring hole and the pin holes .and changing the plate means (sensibly if not necessary) changing the wheel bearing too .likewise if doing a rear bearing you would be well advised to examine the backplate thoroughly at the time.

[addy]

Found a pair of back plates to fit Calibra, a pair to fit Senator. Both of these are from Germany and cost £130.08 plus £10.08 Services from outside UK. Also a pair of Omega ones £150 plus £12.00 Services from outside UK. From the same place. All of them the pins locks into the back plate, not the newer type where they come through it.

From what I have been told, my 95 Omega was waiting around in a warehouse for a while. So might not be a 95, was just registered from new as a 95? Did the earlier Omegas, use parts possibly from Senators for back brakes?

[LC0112G]

Found a pair of back plates to fit Calibra, a pair to fit Senator. Both of these are from Germany and cost £130.08 plus £10.08 Services from outside UK. Also a pair of Omega ones £150 plus £12.00 Services from outside UK. From the same place. All of them the pins locks into the back plate, not the newer type where they come through it.

From what I have been told, my 95 Omega was waiting around in a warehouse for a while. So might not be a 95, was just registered from new as a 95? Did the earlier Omegas, use parts possibly from Senators for back brakes?

Yes. The preface-lift Omega B is basically a Carlton/Senator D/E. Infact, the Carlton was sold as an Omega A in euroland.

[Enceladus]

The backplate part numbers for the Omega B are different to the earlier version used on Omega A/Carlton, Senator B, Calibra and Vectra A, suggesting that they are not interchangeable. So in theory the Senator parts can't be used on your car.
Whether or not they can be modified and made to fit your car is a different matter. You need somebody who has actually done this to confirm.

The modification of inserting the shoe pins from the rear of the backplate applies to the earlier cars as well as Omega B. It's independent of the actual backplate fitted. Hence the revised pins with the cup washers will work on your car but you need to loosen the backplate bolts and move the plate outwards to fit the revised pins. Then move it back and bolt it up again. The bolts require an M10 XZN long (triple square) bit.

For Omega A/ Carlton, Senator B, Calibra & Vectra A
90222355 = LH Rear Brake Flange
90222356 = RH Rear Brake Flange

For Omega B
These are the backplates currently fitted to your car assuming the factory backplates were never previously changed.
90374615 = PLATE,ASSY.,REAR BRAKE CARRIER,LH (NLS.- USE 9156092 5 43 072)
90474616 = PLATE,ASSY.,REAR BRAKE CARRIER,RH (NLS.- USE 9156093 5 43 073)

The backplates were then superseded by these.
9156092 = PLATE,ASSY.,REAR BRAKE CARRIER,LH (NLS.- USE 24436738 5 43 081 AND SUPPLY 24428129 5 43 302,24445691 5 46 211)
9156093 = PLATE,ASSY.,REAR BRAKE CARRIER,RH (NLS.- USE 24436739 5 43 082 AND SUPPLY 24428129 5 43 302,24445691 5 46 211)

The above backplates were then superseded with these.
24436738 = PLATE,ASSY.,REAR BRAKE CARRIER,LH
24436739 = PLATE,ASSY.,REAR BRAKE CARRIER,RH

However to fit the above backplates you also need two each of the below seals.
24428129 = GASKET,PLATE,ASSY.,REAR BRAKE CARRIER
24445691 = BOOT,LEVER,BRAKE CABLE (RUBBER)

[polilara]

Succeeded to find original GM 24436739 from Germany and for the other side unbranded one from Finnish supplier. Both are that style where pin is put from front.

[Enceladus]

What part number was the unbranded one supposed to match? 24436738 to fit an Omega B?

Or was it sold as fitting an Omega A, Senator B, Vectra A & Calibra?

[Doctor Gollum]

They're obviously sides, so expect a different part number left and right...

[polilara]

What part number was the unbranded one supposed to match? 24436738 to fit an Omega B?

Or was it sold as fitting an Omega A, Senator B, Vectra A & Calibra?

Yes, I bought that to my Omega B. I could put them one upon another and take the new pic. I think they are similar (L&R).

[Doctor Gollum]

Your picture is perfectly clear

The difference between them being the slot for the parking brake lever is below the hub... The right one in the picture is 24436738 is the right hand one and it would therefore be reasonable to assume (without looking because I CBA) that 24436739 is the left hand one...

Corrected.

[polilara]

Your picture is perfectly clear

The difference between them being the slot for the parking brake lever is below the hub... The left one in the picture is actually the right hand one and vice versa so 24436738 is the left hand one and it would therefore be reasonable to assume (without looking because I CBA) that 24436739 is the right hand one...

Yes, they are upside down but left one in picture is for the left side of the car I guess...

[Doctor Gollum]

Your picture is perfectly clear

The difference between them being the slot for the parking brake lever is below the hub... The left one in the picture is actually the right hand one and vice versa so 24436738 is the left hand one and it would therefore be reasonable to assume (without looking because I CBA) that 24436739 is the right hand one...

Yes, they are upside down but left one in picture is for the left side of the car I guess...

You are correct, I hadn't initially realised that the face shown is the diff side not the wheel side

[polilara]

Your picture is perfectly clear

The difference between them being the slot for the parking brake lever is below the hub... The left one in the picture is actually the right hand one and vice versa so 24436738 is the left hand one and it would therefore be reasonable to assume (without looking because I CBA) that 24436739 is the right hand one...

Yes, they are upside down but left one in picture is for the left side of the car I guess...

You are correct, I hadn't initially realised that the face shown is the diff side not the wheel side

Yes, picture is from "wrong side" just wanted to show the label without removing it.

[Enceladus]

What part number was the unbranded one supposed to match? 24436738 to fit an Omega B?

Or was it sold as fitting an Omega A, Senator B, Vectra A & Calibra?

Yes, I bought that to my Omega B. I could put them one upon another and take the new pic. I think they are similar (L&R).

So you bought the unbranded backplate as fitting an Omega B, which is fine.

However member addy asked about using Senator backplates on his Omega B? So what's still not answered is whether or not Omega A/Senator B/Vectra A/Calibra backplates can be used on an Omega B? EPC suggests not as they have differnent part numbers.

The old style Omega B pivot pins, with the crosshead, fit into the backplate from the outboard side. The new pins with no crosshead fit through the backplate from the inboard side. Either pin can be used. No need to change or upgrade the backplate. unless damaged. However to fit the newer style pins, without the crosshead, you need to loosen the four bolts and temporarily move the plate outwards so the pins can be installed. That's the GM service instruction.

The same service instruction is true of the Omega A/Senator B/Vectra A/Calibra pivot pins. The new style pins can be used by inserting them from the back of the plate.

Member addy shouldn't need to change his plates unless the locking slot is too damaged or corroded. There is no need to upgrade the pins for the new type if the plates are in good condition. Is's just that the new pin type, inserted from the back, are less likely to pull through the plate as they have a bigger contact area.

[Andy H]

What part number was the unbranded one supposed to match? 24436738 to fit an Omega B?

Or was it sold as fitting an Omega A, Senator B, Vectra A & Calibra?

Yes, I bought that to my Omega B. I could put them one upon another and take the new pic. I think they are similar (L&R).

So you bought the unbranded backplate as fitting an Omega B, which is fine.

However member addy asked about using Senator backplates on his Omega B? So what's still not answered is whether or not Omega A/Senator B/Vectra A/Calibra backplates can be used on an Omega B? EPC suggests not as they have differnent part numbers.

The old style Omega B pivot pins, with the crosshead, fit into the backplate from the outboard side. The new pins with no crosshead fit through the backplate from the inboard side. Either pin can be used. No need to change or upgrade the backplate. unless damaged. However to fit the newer style pins, without the crosshead, you need to loosen the four bolts and temporarily move the plate outwards so the pins can be installed. That's the GM service instruction.

The same service instruction is true of the Omega A/Senator B/Vectra A/Calibra pivot pins. The new style pins can be used by inserting them from the back of the plate.

Member addy shouldn't need to change his plates unless the locking slot is too damaged or corroded. There is no need to upgrade the pins for the new type if the plates are in good condition. Is's just that the new pin type, inserted from the back, are less likely to pull through the plate as they have a bigger contact area.

I definitely didn't loosen the 4 triple square bolts when I put the pins in from behind - I didn't have the tool to undo them. Quite how I managed it I can't remember, I think I spent a long time trying to feed the pin in from underneath the trailing arm before trying from above and then it just slipped in
On the subject of service instructions...... I have lost count of the times I have followed Haynes and spent days doing a 5 minute job, hopefully the GM service instructions are more accurate

[Nick W]

On the subject of service instructions...... I have lost count of the times I have followed Haynes and spent days doing a 5 minute job, hopefully the GM service instructions are more accurate

They're German, so they certainly won't be simpler.


For instance, have you seen the GM tool for changing rear wheel bearings? 


A Japanese engineer(for example) would have made the timing belt tools much simpler too.