RE: DIY pressure brake bleeding tool...

["Aaron Bohnen" <bohnen@xxxxxxxxxxxxxxxx>]

Hi Ephraim and everyone,

Thanks for the mail:

> I'll go for anything that works and that saves me money. Kindly email me
> more details about your brake bleeding tool.

Well, there's not much more to tell - it consists of a BMW cap for my 
master cylinder with the floatswitch guts removed (I happened to have 
it in my parts box), a truck-style steel scraeder valve stem from a truck 
wheel (cost me $0.50 at the local tire shop - he literally had a bucket 
full of them) and a crummy hand bicycle pump.

> Add fluid right up to the TOP of the reservoir on top of the master 
> cylinder (leaving some room for air), install valve lid. Pump a few strokes
> with the pump, open bleeder valve at desired caliper, pump a little more, go
> have a look at the fluid coming out of the caliper, repeat, etc. until all
> nice new fluid is seen coming out. Move on to next wheel. Don't forget to
> bleed the clutch slave cylinder at the end as well.

Works like any other pressure brake bleeding system except that you have to 
pump it a little, go look at the fluid coming out of the caliper (it will 
keep coming out while you walk from the hood to the caliper as the system 
normalizes back to equilibrium pressure), go back, etc. Do NOT pump it up 
to a high pressure. You will endanger the brake system if you do. If the 
master cylinder cap leaks a little air that's fine too. We are not trying 
to get a high pressure scene going here, just enough to motivate the 
old fluid out of the calipers along with any air, etc.

After a couple of ounces or so of fluid has been expelled, go back, remove 
the pressure cap, refill the master cylinder reservoir, replace the 
pressure cap, pump a little more and continue in this way.

You will also need the classic brake bleeding used-fluid reservoir. This 
consists generally of a Mason jar with two holes in the lid sized to fit 
the outside diameter of the small size of tubing whose inside diameter fits 
the bleeder fittings. This jar should have at least 2 feet of tubing with 
it - 8" or so sticking in through one of the holes in the lid. You want 
this tubing's end to lay along the bottom of the jar. This jar is used by 
covering the tubing inside with brake fluid so that during bleeding into 
this jar at no time can the caliper suck air back inside.


best regards,

Aaron
___________________________________________________________
Aaron Bohnen                     email: bohnen@domain.elided
- -Ph.D. Candidate, Civil Engineering Department, U.B.C.
- -Technicraft Engineering Services

------------------------------