Technical Think I need a new rear subframe (and alot more besides)...

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Technical Think I need a new rear subframe (and alot more besides)...

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Jun 14, 2016
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So, having neglected my Multipla for too long it has now failed it's MOT with a long list, half of which I should have done last year (but a crappy old fiesta was wasting my time and money).
(I think) I know how to do most of the jobs - injector seal, EGR, front spring, wishbone bush. However, It's failed on corrosion at the top of the rear spring mount point, which from what I can see is the subframe. I have seen that these are a common problem, and after pondering scrapping it, and deciding against it after my wife refused to let me have an Alfa 159 sportwagon - of in fact, any other car (on the basis we dont actually need 3 cars, as we barely need 2) I have decided I would like to restore it, so we can go on holiday in reasonable comfort in a few years when we have had child number 3, and multipla's will be all but extinct.
So, I know others have removed the subframe and cleaned it up, and I could do that, but I think it has rusted beyond that point, I can see holes in the metal around the bump stops. I see you can get new subframes for just under £500 on ebay, I was thinking it might be best to scrap the old one and get a new one (and add extra protection before fitting), and do any other work, like swing arm bearings (and clean up the swing arms) whilst it's off. Which bits do I need to check for integrity? I will try and get some photos.
Further plans would be to do the whole front suspension, change the cam belt etc and remove and the touch up any rust spots under the car (there's a few, but nothing chronic) and protect with some kind of wax coating. Oh, and sort the brakes as they are shocking despite new discs and pads a year ago.
Is this a good idea? - its an 06 1.9 mjet 115 (or 120 if thats a thing)
Thanks
Lewes
 
Sorry, I ramble too much, I have decided I am going to restore the car (it's a no brainer when the other option is having less cars!!!).
Specifically, I am asking if I should buy a new subframe? like, is it worth it, or is their a cheaper alternative? I have also been browsing autodoc and discovered you can get the swing arms too, although, these seem to be made of just a huge chunk of steel, so I'm guessing despite being very rusty they should be fine for many years before their strength was compromised? so a a bit of a clean up, rust converter and some paint should be fine.
 
The swing arms are nice iron/steel castings. As long as the seats for the swing arm bearings have not pitted badly, there's no reason why they wouldn't come up very nicely if given a shot blasting. As you say, they are a solid bit of kit, so corrosion to the body of the arms won't be an issue. I'd qualify that by saying I've never seen an arm that's rusted through.

As for the subframe, it very much depends on how far gone your existing one is. To gauge that, the best way is to take it off the car. Areas to look out for are the centring cone-pressing (i.e. the seat for the top of the spring) and the cage that accepts the top of the damper. Both of these parts are made in a lighter-gauge of steel than the rest of the subframe. If rust is a problem for those areas, I reckon a competent metalworker could fabricate repair sections and weld them on. It would then come down to cost whether that's the more economical way of doing things. The rest of the subframe is pretty robust. Unless your car has really been exposed to the elements, I wouldn't expect corrosion to be an issue there.

Either way, personally I'd get the subframe shot blasted (even a brand new one) and then repaint with something like epoxy Rustbuster (along with the swing arms), and give the inside of the main cross tube and the swing arms a good coating of Waxoyl, Dinitrol or similar. If the prep is good, that would give you a rear end set-up that would laugh at the worst weather and last for years. I'd also use an adhesive-lined weatherproof heat shrink to cover all of the rigid brake lines, for similar reasons.

For the rest of the body, it's a very solid spaceframe. The only place I've seen corrosion as an MOT problem is where the inner face of the outer sills meets the underside of the floorpan, roughly speaking somewhere below the front doors. It's all simple folded sections, so again a plate repair would be straightforward, if it's needed. Waxoyl/Dinitrol inside those outrigger box sections, just for peace of mind. There are a couple of bungs that can be removed to get inside them. Having a look inside with a borescope (dead chap on Amazon or eBay now) would give a good idea of their condition. It's ironic that a couple of friends with BMW's (especially the 3-series) of similar age to my Multi have seen them go to the scrap heap recently because of terminal rust, where my supposedly dissolve-in-the-rain Fiat has faired much, much better.
 
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I scrubbed rear frame down on my mk1 a year ago ... was much better than it looked and very thick base metal.

Some good threads on swing arm bearings and the subframe bushes.

WMF advice sounds spot on as usual.

Let us know how you get on.
 
Thanks for the input, yes, I have seen the various how to threads on the bushes and bearings, so will be certainly using those. I will try and get the subframe off soon, but need to make sure the Avantime gets through the MOT first (it's on Monday) once thats sorted I'm safe to embark on this.

Is it relatively straightforward removing the subframe? any pro tips? I saw that you can disconnect the ABS sensor from the rear door, what do I do about the brake lines?

Will keep you posted
 
Unplug the ABS sensors at the connectors under the carpet, as you've said, prize the sealing grommets out of the floor and pull the cables right through. Split the brake lines at the rigid pipe connections just forward of the subframe cross tube, towards the nearside. Give those unions a really good soaking with penetrating oil a few days before you do the removal and go back to soak them again every day. They are prone to seizing and if they do, they will rip the brake pipes apart. Also, give the connecting/tensioner nuts for the handbrake a bit of penetrating oil to help with getting them to part.

Once the above is freed off, it's just a case of undoing the four main bolts holding the subframe in place. Access to them isn't a problem - plenty of room to get a breaker bar in there if needed. When I drop the subframe and I am on my own, I put a scissor jack under the back end of each of the trailing arms and another (or a trolley/bottle jack) under the middle of the subframe cross tube. It's not a hugely heavy assembly, but cumbersome and difficult to control the lowering when there's only one pair of hands available. The bolts are all that hold the subframe in place - there are no locating dowels or lugs, so the frame will come free as soon as the bolts are slackened off.

If you've got an old sheet of chipboard or OSB to hand to put underneath, it makes dragging it out from under the car easier.
 
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The swing arms are nice iron/steel castings. As long as the seats for the swing arm bearings have not pitted badly, there's no reason why they wouldn't come up very nicely if given a shot blasting. As you say, they are a solid bit of kit, so corrosion to the body of the arms won't be an issue. I'd qualify that by saying I've never seen an arm that's rusted through.

As for the subframe, it very much depends on how far gone your existing one is. To gauge that, the best way is to take it off the car. Areas to look out for are the centring cone-pressing (i.e. the seat for the top of the spring) and the cage that accepts the top of the damper. Both of these parts are made in a lighter-gauge of steel than the rest of the subframe. If rust is a problem for those areas, I reckon a competent metalworker could fabricate repair sections and weld them on. It would then come down to cost whether that's the more economical way of doing things. The rest of the subframe is pretty robust. Unless your car has really been exposed to the elements, I wouldn't expect corrosion to be an issue there.

Either way, personally I'd get the subframe shot blasted (even a brand new one) and then repaint with something like epoxy Rustbuster (along with the swing arms), and give the inside of the main cross tube and the swing arms a good coating of Waxoyl, Dinitrol or similar. If the prep is good, that would give you a rear end set-up that would laugh at the worst weather and last for years. I'd also use an adhesive-lined weatherproof heat shrink to cover all of the rigid brake lines, for similar reasons.

For the rest of the body, it's a very solid spaceframe. The only place I've seen corrosion as an MOT problem is where the inner face of the outer sills meets the underside of the floorpan, roughly speaking somewhere below the front doors. It's all simple folded sections, so again a plate repair would be straightforward, if it's needed. Waxoyl/Dinitrol inside those outrigger box sections, just for peace of mind. There are a couple of bungs that can be removed to get inside them. Having a look inside with a borescope (dead chap on Amazon or eBay now) would give a good idea of their condition. It's ironic that a couple of friends with BMW's (especially the 3-series) of similar age to my Multi have seen them go to the scrap heap recently because of terminal rust, where my supposedly dissolve-in-the-rain Fiat has faired much, much better.


This is my next piece of work I need to get done so many thanks for the information.

My right bump stop has dropped and is in the middle of spring. I am going to go the route of removing springs, getting some steel fabricated and welded to hold the bump stop in place.

I will then wire brush the sub frame and get it painted and put new springs in when putting back together.

I may get the front done also as my multi seems to make a clink sound over speed bumps at slow speed.

Anyone else have this issue?
 
Hi.

Sounds like front drop links
These are a week component, say £10 to 20 or so each. Easy to fit them.

Post from Widemouthfrog recommends Meyle Heavy Duty 22 3 19
in thread about Glopsy.

When mine next go I am going to try these
 
So, after a year of no progress at all, I have finally got some motivation to get the car sorted. I spent yesterday getting ready to drop the subframe (thanks to widemouthfrog for the help on this post and explanations elsewhere on the forum). The plan had been to drop it, but I ran out of time.
So far I have:
Completely removed one abs sensor, and cracked the other - but disconnected it.
Removed the brake lines after the rubber hose (which is clamped), but only one side survived - but I have done brake lines before so have tools/pipe to replace. I have also unbolted the bracket that holds the hose to the subframe.
Removed exhaust cat-back as couldn't see how I would get the subframe out from under the car as the back-box would be in the way - it required me to cut some of the exhaust hangers, but i need a whole new exhaust anyway (well, the front flexi bit has a huge hole, and the middle box can't have long left due to rust).

My questions are:
how do i remove the broken abs sensor? can it be knocked through if it take the drum off? Also, if I cant repair it, is the sensor different for drum brakes, as I have found no mention of disc/drums on the items, but have seen mention of people buying the wrong one!
I am intending on fully restoring the subframe, it needs welding to the bump stop cup and i want to completely restore it (hopefully shot blasted and powder coated or similar), is it best to remove the shocks and springs before or after removal from the car?

I have recorded the process, so once I have actually dropped the subframe I shall put it together and put it up on youtube to help others as it seems a common job but theres no video of it yet.

Thank you
 
So, after a year of no progress at all, I have finally got some motivation to get the car sorted. I spent yesterday getting ready to drop the subframe (thanks to widemouthfrog for the help on this post and explanations elsewhere on the forum). The plan had been to drop it, but I ran out of time.
So far I have:
Completely removed one abs sensor, and cracked the other - but disconnected it.
Removed the brake lines after the rubber hose (which is clamped), but only one side survived - but I have done brake lines before so have tools/pipe to replace. I have also unbolted the bracket that holds the hose to the subframe.
Removed exhaust cat-back as couldn't see how I would get the subframe out from under the car as the back-box would be in the way - it required me to cut some of the exhaust hangers, but i need a whole new exhaust anyway (well, the front flexi bit has a huge hole, and the middle box can't have long left due to rust).

My questions are:
how do i remove the broken abs sensor? can it be knocked through if it take the drum off? Also, if I cant repair it, is the sensor different for drum brakes, as I have found no mention of disc/drums on the items, but have seen mention of people buying the wrong one!
I am intending on fully restoring the subframe, it needs welding to the bump stop cup and i want to completely restore it (hopefully shot blasted and powder coated or similar), is it best to remove the shocks and springs before or after removal from the car?

I have recorded the process, so once I have actually dropped the subframe I shall put it together and put it up on youtube to help others as it seems a common job but theres no video of it yet.

Thank you
Hi,
Drum off punch abs sensor out of arm.
It is impossible to remove the abs sensor without destroying it if there is any rust jamming it in position.
Abs sensors are the same for drum or disc vehicles.
Left and right sensors are different
Plus there are two types of electrical connector depending on year of build.

I suggest removing arms and springs from sub frame before removing sub frame as it's a heavy lump all together.

Do not force the anti roll ball mounting bolts to the arms, the bolts can shear off)-:
It is manageable if you can get one side of anti roll bar off one of the arms .
Best wishes
Jack
 
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Many ways to do.

I kept wheels on and dropped whole subframe as one lump but needed helper. Mechanics idea ... worked well.

Make some marks to get it back on square /same position on body.

There is a good thread on here, the one with wmf pictures on. Last live about 2 or 3 years ago.
 
The supply of ABS sensors is becoming a bit of a problem. At least the known-brand ones is. I think Bosch must have stopped making them. The part numbers to look out for are:

NSF
Round plug: Fiat 46520005; Bosch 0 265 007 038
Square plug: Fiat 51705195; Bosch 0 265 007 561

OSF
Round plug: Fiat 46519886; Bosch 0 265 007 039
Square plug: Fiat 51705196; Bosch 0 265 007 560

NSR
Round plug: Fiat 46838609, possibly 46842228?; Bosch ?
Square plug: Fiat 51705197; Bosch 0 265 007 563

OSR
Round plug: Fiat 4683610; Bosch 0 265 007 550
Square plug: Fiat 51705198; Bosch 0 265 007 562

The round plug/square plug thing: Earlier models (up to around 2003/4 ish? have a round white two pin plug that looks as though it's made out of hard nylon. Later models have a square black plastic body with a typical clip on the side. I think Fiat switched back and forth between the two at least once in the production life of the Multipla, so can't guarantee an exact chassis number cut-off.

As you can see with my gap in the part numbers finding the rear sensors, especially the round ones, is becoming a problem. The part numbering logic for the square plug type is a lot more consistent on the part of both Fiat and Bosch than for the round plug. From digging around parts pages, I think it may be possible to use a very similar sensor/cable from an Alfa; probably a 147, but I need to have a closer look. The sensor itself and the cable plugs look to be the same and there is only a minor difference in the length of cable - not enough to cause a problem. I would always go with the proper Fiat or Bosch parts if you can find them.

Where the subframe is concerned, if you're not in a hurry to get it back on the road, I'd get the subframe off and have a good look at it. Aside from the cage that mounts the damper and the cones that locate the top of the spring and the bump stop, the subframe is very solidly made and it would take a hell of a lot to make the main structure rust through. The price of a new subframe would pay fro an awful lot of metal fabrication work by a decent local fab shop, and you can follow it up with good quality powder coat or better still a two-pack epoxy spray. Don't forget to prize the end caps out of the main cross tubes and apply a liberal coating of Dinitrol or Waxoyl internally, then re-seal the end caps with a PU seam sealer. Even if you bought a new subframe, that is all work that you'd have to do anyway if you want an end product that laughs at the elements. The swing arms are equally robust and respond well to a loving refurbishment.
 
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SPUDIT2003:

I don't know if my photo-shoot is still around from when i did a similar job, not that long ago, it might help you out.

By the way, do yourself a favour and put two grease nipples in to your swing arms whilst you have them off - it'll make 3 monthly greasing easy peasy (it'll also prolong the life of your new bearings)
 
Just seen this on ebay:

https://www.ebay.co.uk/itm/FIAT-MULTIPLA-Bosch-Sensor-wheel-speed-0265007036-1-6-REAR-LEFT/133399470851?epid=1209355936&hash=item1f0f3a6303:g:bt0AAOSwZOVZtu0N

If that is correct, the Bosch part number for the one I missed out in the post above is 0 265 007 036, which is kind of in series with the two front ones (and suggests the OSR is 037?). However, the Fiat P/N in the listing is nothing like I've got. It does have the white two pin plug and it looks to be the correct length. At that price, it could well be worth a punt.

If you're lucky enough to get on the forum ePER when it's not having a hissy fit, that may give some definitive answers.
 
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Thanks all for the great responses.

I am going to remove the arms as advised,as I'm not very strong so dont want a big heavy lump to move if I can help it, so just need to work out how they are attached - do I take the bearings out? (I will be replacing them anyway).

When you say put some marks on the body - do just mean around the corners of it so I can see where its mounted? Sounds like a good tip I hadnt thought about putting it back on just yet!

Thanks for the ABS sensor part numbers I will ensure they match up, I do atleast know I have the black square connector as I (eventually) manged to disconnect it.

I am intending on getting the subframe repaired (bump stop cone rusted away, but I will also check the integrity of the cages at the top), and then coated, I am hoping I might be able to get it galvanised, but depends on the cost, then I would paint it with something long lasting. I had pondered buying a new subframe when the car first went off the road, but it looks as though they are NLA, the only ones I can find are around £350 delivered from Italy, they look in reasonable condition but as you say, I can get it repaired for much less and of course would still need protecting. I am wondering if I get it galvanised the main cross tubes would then be protected internally as its hot dip? I am probably going to do something a bit less thorough on the swing arms - as they are seem to be less vulnerable than the subframe I will get them rubbed down and painted still, but more a DIY thing (unless getting it done professionally isnt too expensive)

This is big project, I am in no particular hurry (although am hoping to complete it sometime next year) - I am going to just do the whole car as front suspension needs replacing too.
 
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