Nuts and bolts

[Garytwingo]

I am in the middle of upgrading the front suspension including control arms and all bushes. What I am not replacing I am cleaning up and painting. The only problem is a lot of the parts do not come with new nuts or bolts and I don't want to use the old rusty ones. Where can I get new ones from? Can I just go to a hardware store with the old ones and replace them that way or is it better to go a main dealer and buy originals?

[Del]

You can buy generic nylo nuts for the ball joints at motor spare shops like GSF or ebay. The two bolts holding the bush holder to the body are really BMW specific. Finally, the 13mm? locking nuts holding the front droplinks to the control arm incorporate a flattened section to hold them squarely to the control arm (they are the same on the rear at the trailing arm bracket). These are BMW specific and I appreciate from by own experience that they do degrade with age. From memory they don't cost that much from BMW, about 0.50p each?

[Garytwingo]

Thank you for that. Looks like a trip to the dealer is on the cards!

[bentley-boy]

When I fitted new Meyle ball joints to my front wishbones they came with new nuts, however I too wanted to replace the other fastenings. A call to the dealers was giving me quotes of £4 odd just for a nut, hate to think of the bolt prices so I refitted the original. I hate paying through the nose for simple generic stuff. However be wary of buying aftermarket fasteners, the market is awash with cheap and nasty sub standard fasteners. I never got around to pricing the items from an aerospace quality supplier but could well be cheaper than the dealers?

BB

[siwilson]

Most BMW nuts and bolts are shared across many models and not that expensive. It's only the special ones that can be a bit steep. As a result I use new most of the time.

If you replace the front shocks then the two lower bolts are one time use only and so is the nut.

[Mike Fishwick]

Even new fasteners will soon corrode in the UK's salt-laden environment! Why don't you de-rust the old ones, then prime and paint with Smootherite, adding a final coat after they have been installed? It is easy enough, and adds a couple of days to the work, but it will comfortably outlast the original zinc plate. I painted all mine about ten years ago, and they still look fine.

[Garytwingo]

Thanks for all the advice.
I think I may do a mixture of what has been said and buy new ones but also paint them. I would hate to park on a polished manhole cover and have rusty nuts on display!!!

[Brian4]

If you are replacing the control arms complete most seem to come with new bolts and nuts so should be ok. If you are just refurbing and painting the control arms just note that the nyloc huts for the inner. outer and steering ball joints are metric fine thread not the normal thread pitch and the bolts are high tensile 8.8 or 10.9, most hardware store ones will be lower than this. The type of bolt used is marked on it's head.

When replacing nuts/bolts you will also find that the new ones will need a bigger socket than the one used to undo the original. ie if you used an 16 mm socket to undo the replacement will be need an 17 mm socket.

[Mike Fishwick]

The easy way to paint bolts is to take a peice of thick cardboard box material, and cut a load of X-shapes into it. Bolts of all sizes can then be pushed into the X-cuts, and easily primed then painted.

Old nuts and bolts are best held in a vice and wire brushed - if you do not have a vice, dump them in a jam jar of phospouric acid rust remover, then rinse and dry before paintin.

[brilie]

You can always use stainless steel nuts and bolts.
These will not corrode and also look nice and clean at all times.
I replaced most nuts and washers that are visible under the bonnet
On mine and I'm very pleased with the result.
A local fixings firm will have most of what you want I'm sure
Cheers brian

[bentley-boy]

I could well be wrong but I think stainless nuts/bolts will not have the necessary tensile loading and therefore should not be used in high stressed applications.

BB

[brilie]

You can get different grades thar is true but I have only
Replaced nuts and washers not bolts and only on visible non stress
Applications ie holding holding the engine in

[Brian4]

Agree with Bentleyboy high tensile stainless are harder to find and torque settings are different because there is less friction with stainless threads. Fine for non loadbearing bolts but not for suspension etc replacement. bit of bling is fine.

[Mike Fishwick]

I recently bought a load of hexagon-headed self tapping screws with airframe washers for the various plastic bits underthe car, such as the wheel arch liners - about £5 for 50 of each.

It's not so much the tensile strength of stainless steel, but the shear strength - the Izod number - which rules its use out for many applications which are stressed in shear such as our rear damper lower mounting bolts, or where there is a step in the diameter, such as some motorcycle wheel spindles etc.

[pingu]

I've used stainless domed nuts (and washers) to hold on the throttle tubes on the M as the chrome-plated originals looked horrible. The down-side is they are not magnetic, so if they are dropped on dis-assembly they are much harder to retrieve.