Advice Appreciated - Z3 with Very Rusted Inner Sills Jacking Points

[whippetoven]

Hi everyone,

Sorry for not posting much since joining - life has got in the way a bit at the moment! I've finally found some time to come to do some 'preventative maintenance' under the beloved Zed and what i (and the last MOT tester in my defence!) had thought was 'surface rust' on the inner sills has turned out to be much, much worse than feared. The extent was revealed after a good poke with a screwdriver To make matters worse, the car has just had £1500 spent on the oily bits (new head and headgasket/chain/camsaft seal/chain guides/front brakes/springs)

I am sentimental about the car and would like to get it fixed up if possible (it's an MOT failure now if tested tomorrow!) Question is, has anyone here ever had to fix one this bad (see pics) and given where it is, is it even possible to get it MOT passable at this point?? Would be such a shame to lost it as mechanically in most areas she's now very sound .....

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I would like to get the outer sill off to see the true extent of it but i understand it is a bit difficult without it being on stands (which i dont have) ...

 

[Bampz]

Difficult without stands but possibly doable , I would buy or borrow some axle stands to as you say remove the outer cills to check extent of any rust , if that bad it is possible to cut the rusty part of cill out and weld in a new piece , @Sean d did this on his rebuild getting the replacement part from one of the resident breakers on here

 

[mrscalex]

HHmm. Doesn't look great to be honest. Sean did do exactly this job (a pretty much full inner sill transplant) but he's a professional and it would be very expensive otherwise.

Unless the sentimental attachment is such finances are no objective you might be better off just looking at patching it. But I'm not sure how effective that would be. I'm afraid some would consider it beyond sensible repair. But how many of us here are sensible...

 

[whippetoven]

Thanks for the replies ... to be honest sorting it myself would be way beyond my own abilities. It would be a professional job I'd have to seek but I'm fearing if chopping out the quarters (if I can find some decent ones) for replacements is going to be the job, it may not be worth the (large?) expense despite my emotional attachment to the car Have decided to take it to my local indy BMW guy Noel Butler to pass final judgement next week .... will keep people posted

 

[Althulas]

Axel stands are reasonably priced. I have a set of the Halfords advanced ones think they are about £35 but these are similar from tool station https://www.toolstation.com/axle-stand/p83498#reviewTab

worth getting the cover off and angle grind the surrounding areas with a wire cup attachment to sound bare metal and give it a acid etch and spray weldable primer to protect the good metal. That would be the prep work out the way for the cost of your own time and materials.

Now you can see where your at to what needs chopping out. Hopefully you could get the sections you need to save some fabrication.

For the repair several ways to approach it.

A mobile welder which is obviously the more expensive option but saying that buying a mug welder to do it yourself may be not far off the price of someone doing it for you and taking the time to learn to weld but that would have its own rewards learning a new skill set.

I don’t know if one the Zed sheds would be able undertake such a repair @Lee anyone else?

 

[whippetoven]

Cheers for the reply Althulas - would love to have the time (and space!) to learn to weld myself but just don't at the moment - i think i may have to be brave and tackle the prep as you suggested though (as i've got fists of ham but little to lose now tbh). Daft question but here goes - assuming i put the axel stands under the jacking points, where best to jack the car from?? (i have a trolley jack) Or do i put the stands elsewhere??

 

[Lee]

Axel stands are reasonably priced. I have a set of the Halfords advanced ones think they are about £35 but these are similar from tool station https://www.toolstation.com/axle-stand/p83498#reviewTab

worth getting the cover off and angle grind the surrounding areas with a wire cup attachment to sound bare metal and give it a acid etch and spray weldable primer to protect the good metal. That would be the prep work out the way for the cost of your own time and materials.

Now you can see where your at to what needs chopping out. Hopefully you could get the sections you need to save some fabrication.

For the repair several ways to approach it.

A mobile welder which is obviously the more expensive option but saying that buying a mug welder to do it yourself may be not far off the price of someone doing it for you and taking the time to learn to weld but that would have its own rewards learning a new skill set.

I don’t know if one the Zed sheds would be able undertake such a repair @Lee anyone else?

Unfortunately nothing I can help with at the moment. You can buy these from BMW so you just need someone to weld them in.

 

[whippetoven]

Unfortunately nothing I can help with at the moment. You can buy these from BMW so you just need some to weld them in.

No worries Lee. What precisely can you buy from BMW ? The inner sill sections?

 

[Lee]

No worries Lee. What precisely can you buy from BMW ? The inner sill sections?

Yeah the inner sills. Or talk to 'Spurfaninacoupe' he cut the last ones out that Sean used to weld in. If thats the road you want to go down.

Get a flappy wheel on a grinder and see how they tidy up.

 

[t-tony]

You can jack the front end by placing the trolley jack under the rear mounting (lollipop) of the front lower arm. Then place the stands under the main chassis box section. That will allow plenty of working room at the sills.

Tony.

 

[whippetoven]

You can jack the front end by placing the trolley jack under the rear mounting (lollipop) of the front lower arm. Then place the stands under the main chassis box section. That will allow plenty of working room at the sills.

Tony.

Thanks for that

 

[Althulas]

Also can Jack up the rear under the diff but make sure not to place the jack under the aluminium cover and place your stand on the rear rail near the jacking point. If you have a look at some of the earlier episode of the mutt build

View: https://youtu.be/TmuFk7ObzQA


you can can get a picture of the construction of those areas, sorry I can’t remember which episode will be of the most use but worth a skim through some of them.

I hope when you get the outer ones off and have a good clean up that you can get away with a patch repair.

 

[t-tony]

Place a rubber or wood pad on the jack cup when jacking under the Diff.

Tony.

 

[mrscalex]

No real need to risk jacking under the diff. Jack under the rear beam. Well that's all assuming you have a decent size trolley jack. Hard work in this sort of location with a £30 Halfords job.

 

[t-tony]

There is no risk jacking under the Diff.

Tony.

 

[Sean d]

From memory, the inner sills from BMW are around £260 per side, add around £700 per side for labour

 

[137699]

If you have not seen it, this is worth a watch for ideas of how to deal with that corrosion...

https://www.redish-motorsport.com/Z3MS50S54UndersideRestoration.html

 

[mrscalex]

From memory, the inner sills from BMW are around £260 per side, add around £700 per side for labour

Funnily enough I remember you quoting the figure of £700 at the time and I nearly mentioned that in a post. Glad I didn't as I thought that was total! But it was what I was alluding to when I said a patch it approach might be the only viable option.

 

[Woodsta888]

I do wonder why the garage who did all the other work didn't see this rust underneath, particularly when doing the brakes - hard to miss. Is it the same garage that did the MOT? I'd go back to the MOT garage and ask why they deemed it roadworthy as you've spent a load of dosh on the oily bits assuming as it had passed, it was surface rust underneath. I feel for ya!

 

[mrscalex]

I do wonder why the garage who did all the other work didn't see this rust underneath, particularly when doing the brakes - hard to miss. Is it the same garage that did the MOT? I'd go back to the MOT garage and ask why they deemed it roadworthy as you've spent a load of dosh on the oily bits assuming as it had passed, it was surface rust underneath. I feel for ya!

Not sure they're allowed to root around and exploit flakey areas. @t-tony would know.