Hi all,

Having renovated my bike I noticed a lot of the bolts on the bike have begun to rust (I live about 100m from the sea) - even after I renovated all of them, sprayed a couple of coats of clear coat over them and "baked" them in an oven before putting them back.

The sea and salt air here plays havoc on all things mechanical! ...

So I've decided I'm going to replace all the nuts/bolts/screws on the bike with new stainless steel ones (preferably marine grade if possible).

My question is this:

I believe one should be careful in terms of the strength of the replacement bolts etc. I've also heard that stainless steel has more of a tendency to crack under strain / vibration than the usual steel.

Most of the nuts / bolts/ screws etc I have no fear about replacing.

However, there are some crucial ones which I am weary about replacing, namely:

1. Engine / Frame mounting bolts.
2. Rear shock absorber bolts
3. Brake caliper mounting bolts
4. Brake caliper bolts themselves
5. Final drive / driveshaft bolts

What are your feelings about this and should I be concerned as much as I am?

Thanks in anticipation.

Barry

http://cgi.ebay.com/ebaymotors/BMW-K100RS-Stainless-Steel-Screw-Kit-Bolt-Kit-_W0QQcmdZViewItemQQhashZitem35aef202b6QQitemZ230568362678QQptZMotorcyclesQ5fPartsQ5fAccessories

I have had stainless bolts and nuts on my R100RS for more than 25 years now without problems. All of your concern list too. All year driver (the more snow and ice, the better) , and they put tons of salt on the roads here in winter time.
Remember some anti fretting paste , nickel or copper grease or similar stuff. If assembled dry you are looking for trouble on disassembly day.
Greetings from Denmark
Poul

I´ve been replacing old screws with stainless ones, with no problems, only have to be carefull that the new ones are the same grade or superior than the originals. Regarding the salt enviroment youll have to keep the bike clean and flush it with clean water because stainless steel will rust by salt crude. For final drive to arm and rear shock ones I´ll preffer galvanized screws, just for peace of mind.
Best regards
JAP

The point made by Poul is actually quite crucial when you live in a damp climate and even more so when they use salt on the roads.
Electrochemically stainless steel and aluminium alloy mix is not advisable unless you use some special grease designed to avoid galvanic corrosion.
Putting them in dry invites a big wrench dance as they say when some years later you need to remove them. If you don't have access to the proper grease (most marine shops stock it) then use the appropriate grade of Loctite so it fills the complete thread hence stopping the ingress of moisture and that should assure removal later will be possible.

Funnily enough I was just this evening talking to a production engineer who was shaking his head and talking about unconscious incompetence because he had to refurbish a product intended for use outside which was aluminium alloy and had stainless bolts holding it together that had corroded and there was now a major problem of removing them since they were all now locked in place by corrosion.
Regards,
K-BIKE

Thanks K-BIKE....heavy dollops of copper slip? Will that be OK?

Barry,I can appreciate your wanting to replace the fittings due to corrosion and your environment, but may I suggest you think very carefully about substituting the original bolts for frame to engine/gearbox connection and other load bearing bolts such as the rear shock connection (with anything other than original spec). There is plenty of information to be found on various fastener sites on the web, but keep in mind that some S/S grades like 316 can be (only) 1/3 0f the tensile strength of a grade 8.8 equivelant bolt. This may never be an issue in itself but there are also other peculiarities with S/S, like work hardening from vibration.
Safety must always be foremost in our minds, particularly when offering advice, though your call of course.
For the record, I have replaced numerous small bolts with S/S as well, they look very smick, particularly against the satin black on the engine.
Best regards, Dennis.

Thanks Dennis - you are confirming my suspicions. For sure, safety must come first! I think I will be on the cautious side and leave those bolts as is, possibly cleaning them up again. Everything else goes stainless steel I think....and you're right, stainless steel bolts against a black engine looks absolutely marvellous - it's what I've done - pics to follow shortly this weekend.

Poul says he has had no issues, but it will still worry me enough to warrant not taking the chance, for peace of mind...I want to enjoy my bike while I ride, and not worry about potentially inferior bolts which will put my ass sliding down the road...

Thanks for the good heads up Dennis.

Stainless steel Allen Screws of good quality have a very high tensile strength so have no fear to use them safety wise.
The corrosion of aluminium when in contact with "any" steel is always a problem. I have used in the past loctite on the threads to give a seal between the two. Or at times I have used the gasket Blue seal. As long as the two are covered you will have no problem.
Ajays

Thanks AJays - now I am flipping the other way again and possibly will replace the "critical" bolts with "cap screws" (allen key bolts proper name apparently) of a high-grade (marine grade) stainless steel.

A product called "Duralac" I've used when rebuilding aluminium masts and fitting stainless steel fittings (mainly pop rivets) for sailing boats. Seems to work well as no corrosion has reared its ugly head yet. Also, I've experienced stainless bolts in mild steel "binding", and actually breaking the bolt head off when tightening up the bolt.

As I mentioned a while back in another post when this subject came up previously, another problem with stainless steel is galling which happens where when you screw it in. The thread can start to bind with the screw and a series of fine contact friction welds occurs with the result that the thread tears metal off as it screws in until finally it is so jammed that it snaps off. Given the lower tensile strength I would be very cautious about using stainless steel of any grade including marine, where the fixing is under load.
Regards,
K-BIKE

Now K-BIKE makes me go the other way again...

Hmm, ....... I've said my bit on this. S/S has its place. On a slightly different note, my '88RT has chrome plated socket-head cap screws, 1 per side at the frame to gearbox housing conection (above the foot pegs). Each has a very small hole drilled in through the side of the head, not through both sides of the hex, 1 side only. Does anyone know the purpose of this ?
Regards, Dennis

Somethig like this?
The hole is for securing the screw with a wire.
Used in racing and on aircrafts for example.
Cheers,Wikur!

Wikur has nailed it, the hole is for safety wiring,
Regards,
K-BIKE

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160525098518&ssPageName=ADME:B:EOIBSA:GB:1123

Stainless steel cap screws (Allen) and various others I will always use with confidence.
There is a kit of them here that I use and they are for the Bmw K 100.
Ajays

That looks like a great kit Ajay, and you say you have used them yourself, may have to invest in one of those.

BIG D