Front Subframe replacement

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KevR
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Re: Front Subframe replacement

Post by KevR »

Tinkley wrote:
1. the tyre is OK!.
I bet it's not!
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Tim Leech
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Re: Front Subframe replacement

Post by Tim Leech »

Right so we are 100% correct (as I will get corrected by the forum police again) Mk1 and Mk2 Subframes are apparently different (repeat after me 100 times), but as the chance of finding a Mk1 is scarce I think you should be safe......

Mk2 are all the same as Des (except maybe a 4x4) fitted one from a 16v with PAS to his 14 without.

And relax.
Lots of Motors, mostly semi broken....
Tinkley
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Re: Front Subframe replacement

Post by Tinkley »

Thanks for the help guys. I think it was old corrossion from its life ooop north (17 years round Doncaster) that finally rotted a little too much of the frame away. Quite nasty little trick really as the outside especially engine side had about 10-15mm of oil and grease build up I cleaned off and cheerfully thought, that will have preserved the subframe...

We will see what 32psi on a new wheel does with that tyre! I think it will be OK but only because it is about 15 months old (v supple) and it was only moved a handful of meters after er deflating. I will check the sidewall v v carefully, probably swap to rear as well. Ironically I had done the pressures a few hours earlier.

Trying to get donor subframe off. Unable to get car very high because of position, no front wheels etc, have found most of the bolts and loosened (all on front side of subframe inc octopus run retainers) but cannot locate brake pipe unions to pressure system. Other than 1 bolt on FDV (I think) nearside rear of subframe is it all clips? Do I just tie up the anti roll bar to support all the other piping and the steering rack?. I reckon I have about 300mm clearance one side and less the other under the subframe. The cars on a slope sideways and forwards so is a bit tricky to raise really high and truly get under it. Got most of the last 4 years of leaves , acorns etc off the pipework and it looks OK.

Yup, Tim the Mk2 had quite a few subtle changes to beef it up and the wishbone pin diameter went up, also to help deal with the newer, more powerful engines. Good to know there is no other major difference. Found a rear subframe on ebay France but not a front one.

The 18mm bolt is the rear one and the others 16mm with a 13 for the rear of the anti roll bar. So you have a good memory :)
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Re: Front Subframe replacement

Post by citronut »

Tim Leech wrote:Right so we are 100% correct (as I will get corrected by the forum police again) Mk1 and Mk2 Subframes are apparently different (repeat after me 100 times), but as the chance of finding a Mk1 is scarce I think you should be safe......

Mk2 are all the same as Des (except maybe a 4x4) fitted one from a 16v with PAS to his 14 without.

And relax.
i thought it was only the very early MK1's were different and the early 1.4 and all 4X4's,

then they were all the same once the arm bearings were removed from the sub frame


replacing a sub frame is quite an easy job, you can even leave the steering rack were it lives, just undo the bolts holding it to the sub frame,

mind you dont loose the spacers between the rack and sub frame though

regards malcolm
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Re: Front Subframe replacement

Post by Tinkley »

Thanks Malcolm. Most stuff is going OK. Steering rack separated. I do have a problem with the rear 18mm (across flats) bolts. They just turn and turn, presumably I have to remove interior trim to access the nuts the other side?.
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Re: Front Subframe replacement

Post by Stinkwheel »

Tinkley wrote:Thanks Malcolm. Most stuff is going OK. Steering rack separated. I do have a problem with the rear 18mm (across flats) bolts. They just turn and turn, presumably I have to remove interior trim to access the nuts the other side?.

I believe the interior nut should have been captive to the body (or is memory failing me?)
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Re: Front Subframe replacement

Post by Tinkley »

Thanks Stinkwheel, it makes a lot of sense to be captive. Having dug out enough interior trim to get above the nut position I can't find it. Presumably it is in the hollow box section. That certainly makes removing the subframe harder if even possible, and that's the better car for lack of corrosion, God knows what the other one will be like!!
I must have turned the offside rear bolt at least a dozen full turns with no dropping movement. The nearside is I believe a bit freeer and has dropped v slightly. Much looser feel to the rotation whereas the offside one is still pretty stiff. On a ramp with an air gun maybe it would move, I might try putting vertical pressure on the subframe to see if that 'holds' it. As the donor is still technically salvagable it might make replacing the subframe fun too.
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Re: Front Subframe replacement

Post by Defender110 »

KevR wrote:
Way2go wrote:Surely there must have been a pre-existing weakness in the subframe for this to occur?
Yep - the subframes tend to rust from the inside out, in particular blowing out the side seams, so they're significantly weakened long before you see any problem on the outside.


I don't see that this is anything to do with corrosion, all that bent metal and the damage to the wheel is good metal that has suffered massive impact damage and nothing to do with weak sub-frame IMHO.
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Tinkley
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Re: Front Subframe replacement

Post by Tinkley »

Does not explain the massive rust all along the side seam (not easily visible in pics). Once you have lost the box section there is no strength. It may well have been subframe collapse that caused the wheel damage and not the other way round. I found reference to similar on a French BX/Citroen site so its not unique.
Inside of wheel is perfect, as is inside of rim, and I have plenty of spares though that one was pretty clean, original and not rusty. 20mph max speed at time, not sure the subframe had massive impact but the wheel took a bit!

BTW there was also on French Lebancoin a front subframe from a 16v for sale posted July, may still be for sale. Seine et Marne area - 50 Euro asked. It was in a dark red colour.

If I was refurbing an old subframe I think I'd get it seam welded along the sides for security. It's just an old age and corrosion issue. Most cars are scrapped before they hit 20 (average age is 13) so not many get a lot of this type of problem. Depends on make and model of course.
Last edited by Tinkley on Thu Sep 05, 2013 10:33 am, edited 2 times in total.
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Stinkwheel
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Re: Front Subframe replacement

Post by Stinkwheel »

The 'hidden' captive nut is a problem familiar to MK2 golf owners....

and the best solution is to slice open the floor, re weld the nut to the body and then weld up the slit open part of the floor.

Far from ideal, but maybe the only solution for this BX also?
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Tinkley
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Re: Front Subframe replacement

Post by Tinkley »

The law of Sod applies - the one with the bent subframe will release the rear 18mm bolts correctly. It might be easier to repair the bent car than the bent subframe. Swap engine/box, wings, screen grill, bonnet hinges etc etc if I can get someone to weld in a couple of new cross members in situ. It really needs a little inner wing welding and a little plating right under the VIN plate which will have to be removed to do it....
Otherwise apart from a widened rear around the tailgate (courtesy of BMW) it is in pretty fair nick.

I don't have a welder so my only solution for extracting the subframe with non captive nut is drill a small hole through box section and pour a small ammount of structural epoxy into it. Hopefully it would capture the nut enough. Too much and the bolt will be caught too!.

Ironically if I was a little naughty and swapped number plates too it would be prety hard to say it wasn't the other car! Just the number etched glass would be a bit of a giveaway......
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mat_fenwick
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Re: Front Subframe replacement

Post by mat_fenwick »

Can you not use a hole saw or angle grinder on the donor vehicle to gain access to the captive nut so you can hold it with something?
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Tinkley
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Re: Front Subframe replacement

Post by Tinkley »

Thanks Mat, if the donor was a scrapper I would. As above it may well be easier to transfer engine etc and do the panels on to the donor than sort the 'runner'. Again ironically the 18mm bolt will do up! just not undo. At least the damage on it (donor) is cosmetic and all the subframe and geometry is true, as well as quite a bit less corrosion generally apart from inner wings. Getting the engine out of it (donor) was a doddle (all steering bolts undid properly etc) compared to the other one which was a pig. The donor was a runner with 62k engine and 117k total. Apart from leaking rad it was sound and ran OK- it needed new drop links, only cosmetic as per the 'Engine Swap' thread. Itis a southern car supplied by Concorde Garages in Wokingham, and I bought it from a guy in Yateley where it had been kept garaged. Can't really moan too much, one cost £450 (53k miles) and the other £300 (118k) the latter with 12 months MOT and 2 new tyres.

If I do swap it, I'll do the octopus while the engines out! and swap wishbones around to have a new and one year old set of bushes.

Having had a bit of a reassessment, the good news is the 'runner' is not damaged in the critical area where the front of the anti roll bar sits. On the other side, on the donor, both the 18mm bolts are held in a non captive nut scenario. Maybe I should get that frame off Kitch if its still free.
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Re: Front Subframe replacement

Post by Jaba »

From memory the rear bolts on the front subframe are just normal nuts and bolts. You need to get a spanner on them from the inside of the car. They are to be found in a sort of recess covered in tape of some sort.
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Re: Front Subframe replacement

Post by Tinkley »

Thanks Jaba you deserve a star :D . I hadn't gone quite far enough inside. Peeling back the carpet and about the clutch side of the brake pedal was the aforesaid recess covered in tape. You need a spark plug socket to get to the nut - I have 3 sizes of plug socket for the set and the middle one was 18mm.
I've got the rigid brake pipes off the flexys and have found the wretched brake union which is not yet yielding to the spanner but it WILL. Once the nearside pipe is off I will be able to get to that 16mm on the anti roll bar.
I think I'll just drop the frame slowly so I can access any clips I can't see at the moment. The car it is going on will be easier not least because I can get it significantly higher ie I will be able to get under the middle of the sub frame on my back.
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