Im trying to bench bleed my new MC, when you press in the plunger you should see no air bubbles in the plasic lines right? im having a problem getting the rear bubble free. it seems like im sucking air in. any suggestions? the front, or larger compartment is bubble free.

If you depress the piston in the MC to far you can damage the o-rings and cause it to suck air. :confused:

I always use a piece of round stock steel to see how deep (uncomppressed) the rod hole in the master is, then tape off 3/4 that distance to keep myself in check when I bench bleed it. graemlins/clonk.gif

If it is an autoparts master, take it back, and try another one. You can get a rebuild kit, and likely replace the piston/o-rings. graemlins/thumbsup.gif

How could i break the o ring? i directions say to depress the piston all the way, full strokes. So i need to rebilld it? how long does it usually take to bleed? how many strokes? I got this MC from my uncle who had it in his garage for a while. Is it difficult to rebuild? Im also getting bubbles coming out of the bottom of the back well when i press the plunger... does that also mean the ring is busted? I just dont what typically is suppose to happen, or how long. how can you tell how deep the rod is uncompressed?
frank

Frank,

How could i break the o ring? i directions say to depress the piston all the way, full strokes.If there is debris or rust in the bore of the MC then pushing it to far will create a score or damage the seal. It might have been dried out in the first place. That's why I think you are sucking air and can't bleed the rear resevoir (sp?)

So i need to rebilld it?Yes, or replace it. Just take it apart, then clean it with alcohol and new brake fluid and really inspect the piston for wear.


How long does it usually take to bleed? how many strokes? I got this MC from my uncle who had it in his garage for a while.I usually get 10-15 strokes before the bubbles go away.


Is it difficult to rebuild? Im also getting bubbles coming out of the bottom of the back well when i press the plunger... does that also mean the ring is busted?No, the rebuild is straight forward, a manual might help. It does not have that many parts. Just snap rings, If I remember correctly.


I just dont what typically is suppose to happen, or how long. how can you tell how deep the rod is uncompressedI just use the depth of the hole as a guide. You just don't want to depress it so far that it bottoms out.

A rebuild kit is cheap, but so is an auto parts store reman., unless this is some original MC you WANT to keep.

DG, thanks for breaking it down for me i will head to autozone today. i have another unrelated problem,, do you know of a reference point to say the steering is straight? i took apart my whole front end, i moved the steering wheel to remove a lower control arm bolt, and now its not back in the original spot. I loosely put everything back together including tie rods, and i notice one wheel is turned more than the other?? how can i tell where is straight ahead without the tie rods attached? Is it the pitman arm or center link positions?

I just get it close, and then get it aligned. Maybe you dropped out a shim between the upper A-arm shaft when you pulled the front end apart.