Brake help

[de3en16]

I'm having problems with my brakes being spongy and pulling to the right. My master cylinder and booster are stock 90 blazer, everything else is new Jb7 from a 3/4 ton suburban. With the engine off and the cap off the reservoir brake fluid will squirt out of the chamber closest to the vacuum booster even with light peddle pressure. It will stop at about halfway through the peddle stroke after that the peddle is spongy to about an 1in off the floor. At high speed the blazer will pull hard to the right with light to med peddle persure. At low speed I can push as hard as I can I can lock up the left front. I've tried bleeding a few times I've got a power bleeder on order.

I'm thinking my master cylinder is going out, one of the internal seals has failed.

If my master cylinder has gone out witch one is would be better hydro boost or vacuum boost?


http://m.napaonline.com/Tablet/parts/PartDetails.aspx?Id=NBB501056_0136010790

http://m.napaonline.com/Tablet/parts/PartDetails.aspx?Id=NMAM2414_0358747462

http://m.napaonline.com/Tablet/parts/PartDetails.aspx?Id=NBB527248_0136010786


Thanks for any and all help. Jim

 

[dremu]

Spongy pedal is either air in the system or a leak. I'd rebleed and make sure connections are good (teflon tape on the bleeder screws can help), and if you still have issues then yeah, maybe the master is worn.

If you do replace the master, you must replace it with the type that matches your booster. While a hydroboost master might physically fit, it won't be plumbed right and probably won't even push properly. (The rod from the booster to the master changes from type to type. Been there, done that.)

In your specific case, I'd suggest the master for a vacuum boosted (i.e. gas, not diesel) 3/4 ton like your exemplar Suburban.

-- A

 

[Stomis]

If you're having left to right problems that don't make any sense like you're describing I'd be checking for bent caliper pins or even mismatched large and small bore calipers up front.

PS not to conflict with dremu and no offense bud but TEF tape on a bleeder isn't going to do anything. And if it does its not the way to fix it. Bleeders are straight course thread. There's no sealing in the thread its a tapered seat just like a brake line or AN fitting.

 

[rampage]

Blazers from the factory pull right, it's due to the push/pull steering and nose dive. There use to be a video that 'Car and Driver' or 'Motorweek' had that this as one of their complaints, but that video has been removed from YouTube.
Only known solution for the pulling I'd to go to crossover.
The other problems you describe sound like the front rubber brake lines are expanding. This would be a good opportunity to upgrade to stainless flex lines.

 

[Massacre-77]

I am looking at a hydroboost kit from vanco.
its the best kit for the money that I can find online

 

[de3en16]

I am going to power bleed everything before I replace something. When I swapped in the axles form the suburban to my blazer I replaced everything including the rubber lines and had the drums and rotors turned. I gravity bled everything before I bled it normally, but I don't remember the master cylinder spraying back up into the reservoir.

If I replace the master cylinder the booster will get replaced along with it. The two biggest things is cost and how easily it is on wether I do hydro or vacuum boost. I already have a Parts truck for the peddle and the other parts I will need.

My blazer defiantly has a nose dive it needs new springs bad, I did replace the shocks on the front end about 3 years ago but maybe it's time to check or just change them again. My blazer sees a lot of dirt road driving.

Thanks for all the replies. Jim

 

[diesel4me]

Wont hurt to check the front wheel bearings..if one side is a bit too loosely adjusted,the brakes will feel spongy and have to be pumped up at least once before the pedal firms up!..and it'll pull too..

A Camaro at my friends shop came in "needing a new master cylinder"..so we installed the one the customer supplied,tried bleeding the brakes,and popped a rear brake line..fixed that,then proceeded to bleed it for a good hour,with me pumping the pedal,and my friend opening and closing the bleeders..it would pump up after several pumps,hold a nice firm pedal,but as soon as I let my foot off it,it would either go right to the floor,or halfway down,and if I pumped it ,it would eventually come back up firm again in two or three pumps..

We were baffled for awhile,thought the master cyl was junk maybe??...then my friend noticed a creaking noise as I was pumping the pedal up,and he was at the drivers side front wheel..he said "pump it till its firm again--OK,let off"..the creaking noise turned out to be the car sagging back to its original position--the drivers side wheel bearing was SO loose,you could pull the tire in and out a good 3/8" or so!..and it took all that pumping to push the rotor out !--we put a new outer bearing in it,adjusted it,and the brake pedal was perfect,with NO more bleeding!..
It dont take that much play to make a noticeable problem ,the customer did come back to tell us "hey,it stops GREAT now,and it dont pull to the left any more either"..

 

[de3en16]

Good call for checking the wheel bearings though the my wheel bearings seem good the lower right ball joint is bad enough I don't want to drive it anymore. And part of the left lower shock tab is broken. I'll get this things fixed and see how my brakes turn out plus I've got some new shocks to put in too. I also seen some movement in my frame and front cross member at the rivets on the left but not on the right. I better get the ORD brace kit for the steering gear before the cracks show up.

Thanks for the help! Jim