Brake caliper problems

[.dave]

I have a 1992 GS that I purchased and am in the process of getting into riding condition. I bought a set of HEL brake lines as the stock lines had several different colors of overspray from poor paint jobs by previous owners. The rear brake line was simple to install. The front brake line, however, is a different story. The banjo bolt on the master cylinder threaded in fine. When I was removing the stock banjo bolt from the caliper, it did not feel right at all. I had to use a significant amount of force to keep turning the bolt. Finally got the bolt off and took a look, and sure enough, the threads were pretty mangled up.

I ordered a new (used) caliper off of eBay and went to install it this morning. Using either the bolt that came with the HEL kit, or another stock bolt, I cannot thread the banjo bolt into the front caliper more than half a turn before meeting a lot of resistance. It basically feels like the bolt is cross threaded. Thinking the problem may have been the HEL bolt, I swapped out the banjo bolt from the master cylinder, but still no luck. I also tried using one of the spare stock banjo bolts in the caliper, but also to no avail. This is really starting to frustrate me, and I'm concerned that the force required to turn the banjo bolt further is going to trash the threads on the new caliper that I purchased. Has anyone run into a problem like this before?

[adidasguy]

Wrong size banjo bolt.

While most on your bike are M10 x 1.0, the banjo for the front caliper has bigger threads. It is M10 x 1.25.

Probably the previous owner did not know that and put in the wrong thread size banjo bolt.

1/2 turn and stops means wrong threads.

[Zwerski]

I just did this same swap last week. The HEL bolts were incorrect for my 97. All banjos on mine are M10x1.0. HEL shipped M10x1.25 but have since shipped correct ones to me when I contacted them. You can do that or clean out and reuse the old banjos but use a thread guage to measure the threads on the new caliper. I was told GS banjos come in both thread guages. Also the HEL bolts seemed to have been machined roughly with a lot of burrs on the threads. Banjo bolts should screw in smooth all the way to tight. Finally, make sure the neck on the brake lines match up to the groove in the caliper.

[.dave]

Thanks guys, that's what I figured as well.

I just ordered a 91 caliper and line so that this time I'll definitely have the correct bolt. The one that I previously bought off of eBay is from an 02 if anyone wants it. I'll check the threads to make sure they're ok.

[adidasguy]

'02 is a better caliper. Keep it and just get the correct banjo bolt. The brake line is the same. You really didn't have to order another brake line.

You could have posed a "want to get for free" for the correct banjo bolt. I have a drawer of banjo bolts.

I generally buy 06-09 parts for all my bikes. Even my '92 has 2009 brake calipers! BrianRC's bike Quin has an 09 rear brake now and next week we'll put on an 09 front caliper and SS line.

Parts compatibility between years is interesting.

[sledge]

M10x1.0 v M10x 1.25. The difference is in the thread pitch. Both have the same diameter but the spacing between the peaks and troughs differs. For metric sizes, the thread pitch is given in millimeters per thread.




Banjo bolts are standard hydraulic fittings used throughout the world in all sorts of applications and are freely available if you know where to look. Forget dealers, there will be someone near you that makes up hydraulic lines, they will supply you with the correct size bolt for pennies. They come in 3 lengths 18, 20 and 25mm...and don't forget the copper sealing washers.

Pirtek is the biggest name but there are many many others at it.

http://www.pirtekusa.com/service/main.asp