Fitting racks

[neil_p]

Hi,

I've been advised by SJS to use loctite blue when refitting my racks to my EXP. However, can that be used in conjunction with copper grease to prevent seizing/rusting?

The reason I ask is that I removed all my racks and mudguards to give the bike a good clean, and all the fixing points had rust inside them.

Thanks

Neil

[expr]

Hello Neil, loctite blue must be used on its own away from grease, having said that if you clean out all the threads first with solvent to give a completely dry base, then apply loctite both to the male and female threads, when this cures completely 24hrs it will totally seal out any moisture anyway thus preventing any further corrosion, of which if you wish you could then apply a small amount of clear lacquer over the complete joint to give complete protection, secondly if you are going to be removing the rack frequently you could use the copper grease in conjunction with nylock's if there is room on the frame without fouling any other parts.

How old is the bike, The reason I ask is thorn now use stainless steel braze ons for mudguards and racks and the rear dropouts (rohloff) are cast stainless. The screws should also be stainless steel grade A2 which is 304 stainless it should have A2 stamped on it.

[neil_p]

Hi,

Thanks for the info.  Right, the rack has already been installed (but bolts not fully tightened) with copper grease. If I wanted to remove them and refit with Loctite Blue, what's the best way to remove the fresh grease from inside the braze ons? You mention solvent - which solvent? Would degreaser be ok?

The EXP is 2 years old.... will check the bolts later on for the A2 stamp.

[expr]

A degreaser would be fine, preferably something that evaporates. Copper grease is shards of copper suspended in a viscous medium, Its main intension is to prevent seizure by allowing the copper to self lubricate the two mating parts, Its not really a good rust inhibitor so would be reluctant to use it anyway for the purpose of rust proofing.

To remove the copper grease will take a little time as it tends to bind and adhere to the threads quite well, the solvent that I use is (mek) methylethylketone you could possibly use nail varnish remover which I think is use to be acetone based but this has been removed with some suppliers to make it more green (plannet friendly).


You could also use Methylated spirits to clean the threads out with a very small brush IE airgun (Barrel cleaner)


The age of your bike I would have thought it would have the s/s braze ons.

[neil_p]

Thanks for the info. My next job is to remove all the bolts I reinstalled last weekend, clean and reinstall them. Grrr. 

A related queston... when loctited bolts are removed, do I need to clean off the loctite residue? If so, is there a recommended technique for that?

[julk]

Neil,
A good way of cleaning the fixing points would be to run a 5mm tap through them, this would also ensure that the threads are in good condition.
I retapped my rear lower rack fixing points in the SS dropouts to 6mm and used 6mm bolts which then support a greater weight if needed.
I got my taps from Model Fixings.

I have used a simple blob of bike grease to keep my frame fixings/bolts free from rust for many years now and have only had one rack bolt come loose in that time. That was on a cycle camping trip on a bike used by a large son who specialised in destroying components through over energetic use.
Julian.

[neil_p]

So Julian, does that mean you're using grease only, and no loctite? If so, any suggested torque for rack and mudguard fixings?  I would rather just use grease, as it is then easier to remove/refit racks etc when travelling.

[expr]

Hi Neil,

once the threads have had loctite in and grease kept away you don't need to keep cleaning them. The loctite turns into a white powder when the screw is taken out, but you would need to apply more loctite on installation. As julk has said a good grease will work as well, you will have to keep an eye on coming loose, I would be tempted not to overtighten them, if you strip the thread then you are in a bit of trouble. The loctite allows you to put the screws in without having to over tighten them and keeps them from moving. The down side is you have to apply more each time you refit.

Do you have room for nylock nuts behind the frame, you could have the best of both then use grease and have some form of anti vibration>

[julk]

Neil,
It is true - I have only been using grease and no loctite. I tighten the rack fittings (steel into steel) by hand with normal bike hand tools. I do them up as tight as feels right, sorry no torque values for these.
I do the same greasing for pedals into cranks and cranks onto the bottom bracket spindle except that I follow the recommended torques for these. I have never had any come loose on my bike.

For more delicate fixings I use a torque wrench and follow the recommended values. I have used loctite on a reused Rohloff hub drain screw only to read a post later which advised letting it dry before fitting...

The over energetic son had his racks refitted with longer bolts and nyloc nuts as suggested by expr. This works and is a very good tip for stopping the bolts loosening on a long trip. You do need some spare space for this to work, but on a Rohloff geared Thorn the space is there. It can be a bit difficult on the rear of a derailleur geared bike as the chain on the smallest sprocket can be very close to the dropout.
Julian