Triumphrat

Mancha · 04-19-2006, 12:07 AM

Hi All,

This is a petty, oft-discussed problem, and it probably belongs in teh Twin Forum. Given the responses to my recent "Do we need this forum" thread, howver, I feel the need to show some loyalty and post it here. I've searched the topics, but, Wow, our search function leaves something to be desired.

My basic probelm is how to bleed a brake line. I just installed the Pretech front caliper. Well, it didn't go the way I wanted it to. I didn't have any trouble removing the old caliper and line. I didn't have any trouble mounting the new caliper and line. The problem, of course, was with filling the new system with brake fluid.

As I understand it, whether or not the cap of the reservoir is on shouldn't really matter, correct? At any rate, I tried bleeding the lines both with the cap and without the cap. The problem is, I NEVER had any resistence when I pulled the brake lever. It was always swishy, and easily pulled all the way back to the handlebar grip. This suggests to me that there's a lot of air in the line.

So I pumped on the lever repeatedly, watching the fuid come out. When it was without bubbles, I tightened the bleeder. I still didn't have resistence on the brake lever, but I started going through the routine anyway: pump the lever a few times with the bleeder closed, open the bleeder and watch fluid drip out, close the lever, repeat ad infinitum. The problem is I never built up resistence.

I checked all the bolts and joins: everything was tight.

Unless I'm missing something, I assume air is seeping in. Either it was always in and I'm not getting rid of it (which seems possible given all I've read), or it's getting in through some defective part. Presumably the Triumph handlebar control is not the culprit, as I wasn't having any problems with it before. This leaves the Spiegler line or the Pretech caliper. Because T1 had no problems installing his Pretech caliper, I'm assuming the problem is I'm simply not squeezing the trapped air out of the line. Why?

I hope this is appropriate to post here. I THINK it goes a little beyond the usual newbie bleeding question, although I may be wrong. Thanks for any help you can offer.

Mancha

1409 · 04-19-2006, 12:55 AM

I used one of these clicky Sears sells them!

04BB

Thrux-ton-up · 04-19-2006, 08:05 AM

Mancha - 1st - do you have speed bleeders installed or a brake bleeding setup you attch to the caliper that is a hose with a one way check valve in it?? This way you do not have to close the bleeder screw while holding in the lever - thus not allowing air sucked back in. I have not tried Keiths idea of the mityvac this could work well.

The bonney front set - up is notorious for being difficult to bleed. When I swapped out brake lines I had the best result taking the entire set up off the bike and bleeding it that way. Lever - line- caliper - all assembled. Put a spacer between the pads and bleed the system off the bike. This allows you to move things around - higher or lower and chase the air out of all the nooks and crannies. Once you get resistance,put it back on the bike (with out disassembly of course) and bleed until no air bubbles show.

After you have a good bleeding session and a firm lever another trick that works for me is to clamp the brake lever hard to the bars and hold it there with a zip tie. This puts the system under extreme pressure and forces little air bubbles out. Let that sit over night and then cut the zip tie in the morning. Pump the lever a few times and it should be rock hard ( I'm talking about the brake lever here). Good luck. It may well be worth the mityvac investment. JCW

TBSstunta · 04-19-2006, 09:02 AM

A technique I have the most success with involves a medical syringe and a small lenght of tubing.

Get your minds out of the gutter folks. :-D

Take the cap off the reservoir and remove the fluid from it. Put the tubing on the syringe and fill it with fluid. open the bleeder valve and use the syringe to push fluid through the system. Make sure the syringe is free of air bubbles, just watch Trainspotting if you aren't sure how. Close everything up and there should be no more air in the system.

No lever pumping needed, easy as pie. That or buy some Speed Bleeders.

Spyder94 · 04-19-2006, 09:16 AM

You could always gravity bleed the system.
Mancha, go buy some beer, install your bleeder hose(s) to the caliper, crack the bleeder screw and keep the master cylinder full. After you run a quart of brake fluid through the system by gravity (4 beers). there should be no air in the system.
The vacuum pump is the best way, but no fun. Only takes 1/2 a beer to bleed the system. :-D Steve
:yayyy: :chug:

Mancha · 04-19-2006, 11:26 AM

Thanks for all the advice. I left it overnight and am hoping that when I attack it again this afternoon, the system will have magically cured what ails it. Sounds like stupid optimism, I know, but I hear it sometimes works on our notoriously-diffcult-to-bleed bikes. If it doesn't, then I'll have to buy another six-pack of beer and get dirty.

1409 · 04-20-2006, 04:06 PM

Mancha, did you get your front brake working? :???:

Keith...

Spooner · 04-20-2006, 05:23 PM

I seem to remember that I didn't get proper resistance in my system until I had bled all the air out, tightened the speedbleeder and put the cap back on the m/c. After a few pumps the pressure was there...all swampiness gone.

Mancha · 04-20-2006, 06:43 PM

Hey All,

After another hour of frustration, I took the bike over to a nearby mechanic. For just $25 he finished the job for me. Said he had a hell of a time too, even with a vacuum pump. He said "I had brake fluid going in both directions; down then back up, and finally got rid of all the air". To tell you the truth, I'm glad I gave up.

To be perfectly honest, I can't claim that the Pretech caliper feels immediately and noticeably better. But I recognize that it needs a break-in period.

Mancha

thruxtonone · 04-20-2006, 11:50 PM

Give another update after you get some miles on it. I think you will see a nice improvement.-T1