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Fix leaking fork brace studs

2011 December 27
by Dirty Fingernails

On the /5 BMWs, there is a chrome horseshoe that acts as both a fender mount and a lower fork brace. The studs that connect the fork brace to the fork sliders are part of the slider and can potentially leak. One of mine has slowly leaked on my /5 for years and i haven’t around to fixing it yet.
For this bike rebuild, i noticed that out of the 2 sets of fork sliders (4 sliders from 2 bikes), one leg was leaking terribly due to all the dried oil residue down the front of the fork slider.As i was disassembling the second set of forks, one of those studs came out instead of the nut coming off… so i got to thinking (and got some advice from some BMW pros), i should re-seal all the studs to be safe.

The tools needed for the job are:
The original 13mm nuts.
2 13mm wrenches
a long 13mm socket would help too
vice
channel locks or pliers
a heat gun
and some RED Locktite

Here is the fork leg with one of the studs removed:

Fork slider with one stud removed, another about to be removed.

 

 

Double nut to remove the old stud. Tighten these two nuts tightly together:

Double nut to remove the old stud. Tighten these two nuts tightly together.

 

Loosen the lower nut and it will remove the entire stud.

 

Inspect the threads of the studs. Out of the 2 sets of fork sliders, i had about 6 good studs.  2 were too rusty or bent to reuse. After inspection, i did a quick cleaning on the wire wheel to clean up the threads.

4 removed studs and red locktite.

 

 

I then replaced the nuts on the longer threaded end of the studs. I pinched the middle part of the stud that is not threaded in a vice and tightened the nut as much as i could.

Then i wrapped part of the fork slider with a rag and clamped it in a vice.
I used a heat gun to heat the fork slider to get the metal to expand. I spent a good amount of time heating the legs to a very hot temperature.

I then added red locktite to the threads of the stud and inserted the stud into fork slider by using the nut and a 13mm socket to tighten it into the slider. I went as far as i could, as fast as i could before the slider cooled down.
*** But please look into the fork slider (flashlight helps) and make sure you don’t drive the stud too far into the leg where it will hit the fork tube. If the stud goes too far, it will prevent the slider from operating properly on the fork tube, or severely damage the fork tube.
When the fork slider cools down, and with the use of Locktite, it should create a nice tight seal around the stud and not leak again.

Tightened studs back into fork slider.I backed off the nuts from the stud and Yeah, i used a bit too much locktite.

One Response
  1. January 19, 2012

    Interesting…

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