vacuum problem? bad brake booster?

[yeti_'87HB]

alright, i know you guys will do your best. here goes lol

when i first got my HB i had to change the passenger rear wheel cylinder, so naturally, i had to bleed the brakes. while i was pumping the brake pedal with the engine running, every time i pushed down the pedal the engine would bog a bit, like it was going to stall. but it when i let off, or held the pedal down, it would stop bogging and run fine. and about 2-3 weeks ago, i started running into a problem where i would have to put the pedal pretty much to the floor before the brakes would start to grab.

now, my guess is a vacuum leak somewhere. bad line, bad line connection, or maybe a cracked booster diaphram?

being that it is my braking system, it is quite urgent

[redneck_racing]

if the booster were bad you would have a stiff pedal. main causes of pedal fade is missadjusted brakes. may also have a leak somewhere in the system. or an exturnal master cylinder leak. also only changing 1 wheel cylinder could cause a problem.

[yeti_'87HB]

well, i drove it for about 3 monts after i changed it with no problems. i just re-did the brakes the other day and re-adjusted them and still no change. theres no fluid leak anywhere, the level of fluid in the reservoir hasn't changed.

[yeti_'87HB]

anyone else know what it could be?

[redneck_racing]

may also have a bad residual(sp?) pressure check valve. i'm assumming that you bled the brakes, on the first drum when you first opened the bleeder screw did fluid "shoot" out?

[yeti_'87HB]

yea, i know how to bleed brakes, i did the bleeding process until there was no air coming out, only straight fluid.

[REYXTC]

I've got a similar problem with mine.

[yeti_'87HB]

anyone else have an idea?

[yeti_'87HB]

??????

[VG30E]

Your new cylinder could be bad. Or there is still air in your lines. Hardbodies are one of the hardest brake systems to bleed. all of the proportioning valves and cooling loops make for great places for air bubbles to hide. You may want to rebleed them agian to double check for air in the lines. Last time I unhooked my rear brakes to do some work on my axle I had to bleed them three times before they were good. !st time and drove 500 miles then lost brakes rebleed drove some more then rebleed now seem fine. Hope this helps.

[yeti_'87HB]

well, i've driven about 5000kms(3000miles) and didn't have a problem that whole time...i'll try bleeding them again and see what happens, but it just seems weird that it would take so long to cause a problem

[homewrecker]

There could have been air trapped in the abs pump or around there and that be why it took a while for it to cause a problem.I would bleed all 4 and if there is a problem after that you might be able to see it while bleeding.

[yeti_'87HB]

its an '87, it doesn't have ABS, it doesn't even have power steering or a/c lol

[REYXTC]

Dif you check the check valve before the booster? Mine was bad.

[yeti_'87HB]

where is this check vavle?

[REYXTC]

On the firewall to the left of booster. Goldish color has two or three vacuum hoses to it.

[yeti_'87HB]

alright, thanks man, i'l have to take a look at it...how do you test it to see if its bad?

[REYXTC]

Well its a check valve. So blow from the vacuum side towards the booster, no air should go through. Then blow from the other side(booster) air should blow through.

[mrs.drginazz]

our hardbody was kinda having the same problem..the brakes went to the floor maybe once or twice a month in july and august...then i drove it too work one day..and when i went to stop the pedal went straight to the floor..and i had to pump them to stop...and then wehn this happend i got it home fine...soo my dad told greg to bleed the brakes...well that just made it alot worse...and everyone said that it was the booster..but it was the master cylinder...we replaced that...and bleed the brakes 2 times..and now its perfect..dunno if that helps at all..