brake bleeding question

[78 K-10]

Im right in the middle of bleeding my brakes. I started on the rear drivers side wheel and man was the fluid dark and dirty. but the thing is, even now that weve gotten the clear fluid to come through for a while now but it still seems like we cant get all the air bubbles out. gone through almost 2 of the bigger brake fluid containers, (not the gallon ones) seems like we'll get 3 or 4 pumps with no air then a couple with air and then repeat. i have no idea what is going on. no signs of leaks or anything anywhere in the break lines or around calipers/shoes. my dad did say that a couple times when her was pumping the breaks he could see the master cylinder cover might have been blowing bubbles past the gasket.

 

[crazy4offroad]

I had a similar problem on a different squarebody not so long ago, ended up being a bad master cylinder.

 

[crazy4offroad]

By the way it has more to do with the seal in the back of the mastercylinder- where the plunger goes- than the top seal. If you take loose the MC and there's fluid in the back it's a dead giveaway.

 

[smurph20]

Your right Crazy and when bleeding brakes out you should always start with the passenger rear not the driver

 

[78 K-10]

pass rear huh. damn. ok so how much fluid can it take to get all the air bubbles out? seemed like drivers side rear was further cuz the main brake line follows my pass side frame and then splits on the pass side of my rear diff.

 

[78 K-10]

so if i am going to get a new mc. do you guys think the cheaper ones on summit are ok?

http://www.summitracing.com/search/...art-Type/Master-Cylinders/?Ns=Rank|Asc&page=2

the bendix mc is like 25$ and
raybestos is like 22$
cardone is 17$ mm no thanks
dorman is like 40$.

and if the seal in the back of my mc is bad then its pointless to keep bleeding the brakes huh..

 

[crazy4offroad]

Look into one of those cheap brake bleed kits. Mostly for the clear line that isnt affected by brake fluid. It will help catch the fluid so you dont have to use so much. And yeah if there's fluid in the back of the mc I wouldnt waste any more fluid. And if I were you I wouldn't cheap out on a new one. At least get one with a lifetime warranty.

 

[Swims350]

if in fact your lines go down the PS frame and then fork over the DS would in deed be the furthest. The last ones I done it always ran down the DS frame, but I think after you mention it the 76 2wd NON power brakes the line for the rear was on the PS frame rail.

 

[78 K-10]

ok went and got a new master cylinder and front brake pads. is it a good idea to try to bench bleed my master cylinder? or unnecessary. any tips on bench bleeding the mc and installing it or just pretty basic..

 

[82chevy350]

You do need to bench bleed Then install and bleed the hole system