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Rear Master Cylinder Help

C

czucker

Guest
So I was changing the rear brake line on 1990 K75 and I ended up stripping the threads on the master cylinder.

I was going to try to use one of those Heli Coil kits, but I'm not certain of the thread size.

Anyone know what thread size the brake lines are off hand? Or does anyone have any experience with these thread repair things?

Any help would be greatly appreciated.

Thanks,
Chris Z.
 
czucker said:
So I was changing the rear brake line on 1990 K75 and I ended up stripping the threads on the master cylinder.

I was going to try to use one of those Heli Coil kits, but I'm not certain of the thread size.

Anyone know what thread size the brake lines are off hand? Or does anyone have any experience with these thread repair things?

Any help would be greatly appreciated.

Thanks,
Chris Z.
Click to expand...
I found a good used rear MC on eBay recently and paid less for it than the price of a Heli-Coil set. Besides, do you really want a part that important Heli-Colied? Just my $0.02.
 
I would not trust a Heli Coil to be leak-free. If you must do a repair, consider a Time Sert with Loctite as a sealant.
 
Thanks. The Time serts look much, much better than the Heli Coils.

However, I buckled and found a used cylinder for a decent price. The idea of having a band aid on my breaks wasn't ultimately satisfying.

Thanks guys.
 
czucker said:
Thanks. The Time serts look much, much better than the Heli Coils.

However, I buckled and found a used cylinder for a decent price. The idea of having a band aid on my breaks wasn't ultimately satisfying.

Thanks guys.
Click to expand...

Order a rebuild kit before installing. 18 year old seals and brake lines are not what you want to be relying on to stop with.

Typically you would install the line on the master cylinder before installing on the bracket, then install the swivel fitting on the caliper, right?.
 
That sounds right. I think that when I stripped the threads I must have been screwing the line in at a slight angle. I will be much more careful this time.

As for the rebuild, the seals look absolutely perfect. I can't say whether the cylinder was rebuilt before I purchased the bike (about 5 years ago now), but everything looks really clean and good. New lines are also going on as soon as I receive the cylinder.

While we're talking about break lines and such, does anyone know if I can just walk into a hardware store and pick up those brass washers for the line? I'm short on washers for my new front lines.

Thanks,
Chris
 
czucker said:
Thanks. The Time serts look much, much better than the Heli Coils.

However, I buckled and found a used cylinder for a decent price. The idea of having a band aid on my breaks wasn't ultimately satisfying.

Thanks guys.
Click to expand...

Yeah, a good used one is the way to go, but I would not characterize Timeserts as a band aid. Such engine companies as Allison, GE, Pratt and Whitney and Buccialli have used similar Rosan inserts and Timeserts in their aluminum cases since long long ago. I have done a number of Timesert repairs that lasted thousands of flight hours with no problems.
 
czucker said:
That sounds right. I think that when I stripped the threads I must have been screwing the line in at a slight angle. I will be much more careful this time.



While we're talking about break lines and such, does anyone know if I can just walk into a hardware store and pick up those brass washers for the line? I'm short on washers for my new front lines.

Thanks,
Chris
Click to expand...

Yes, if you are talking of the banjo bolt washers. I have at Advance Auto Parts.

Ralph Sims
 
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