2nd Gen Non-Engine/Transmission Brake Problems

[norcalram]

Well, coming home from work today as i approached the first stop light i realized i han almost NO brakes. As I depressed the brake peddle, I get a really squishy feel and a loud hissing noise which seems to be comming from under the dash. After creeping home using only my Ebrake at lights (that was fun!!) I popped the hood and had my wife step on the brake. The sound seems to be comming from somewhere near the master cylinder but i cant find where. I do seem to have a leak from around the power steering pump and i understand that the vacuum booster uses the pump for vacuum.



Where should i look first for the problem?



HELLLP!

 

[ttbird]

I thought that 98's had hydroboost not vacuum boost. I may be wrong but my 95 has vacuum boost and I know that later on it changed cause I've thought about changing mine if it ever goes bad.

 

[kenny61]

If the bosster was not working the brake pedal would be very hard to push. Check your brake fluid if it is low you have a leak somewhere.



Does the pedal go all the way to the floor? That would be a leak somewhere or a failed master cylinder

 

[mfburns]

I think you may have a leak in the line someplace. My truck has dual systems and I think yours does to. I had a similar feel and the line was leaking but the other system provided some braking. Check the fluid level, fill if necessary, start the truck and step on the brakes and look for leaks. Just my experience with this.

 

[norcalram]

Thanks Guys

Definatly no fluid leak, its stayed at the same level since i bought the truck (new). it sounds like an air HISSSSS under the dash and under the hood somewhere near the master. The pedal does not go to the floor, it feels fairly firm but sometimes "shutters?" when stepped on light or hard.



Any more ideas? It was 27 degrees this morning and i had to ride my motorcycle to work. LOVE the bike, MISS the heater!!!!

 

[kenny61]

if your hearing a hiss of air and not s paying of fluid i would have to guess that the booster is going bad as that is the only thing with air or vacum in it. or does your truck have the hydro boost which runs off of the PS pump?

 

[norcalram]

its a 98 12v so i'm pretty sure it does.

 

[norcalram]

I cant seem to find anything stating wether mine has vacuum or hydro boost or even how they differ. can anyone shed some light on this for me?

 

[B.G. Smith]

One or the other will be mounted to the firewall and the master cylinder will be attached to it. The vac. booster is a roundish flat cylinder, probably 8 to 12 inches in diameter with a rubber hose attached to it. The hydra-boost is a steel mechanism not much larger in diameter than the master cylinder and also fastened to the firewall with the master cylinder coming off the front of it, it has a small cylinder sticking out of one side which is maybe 2-1/2 inches in diameter and there are also two hydraulic hoses attached to the mechanism. bg

 

[kenny61]

More simply vacum boost has one hose going to the booster behind the master cylinder Hydra boost got a whole bunch of hoses with high pressure fittings going to it which run off of the power steering pump