Hello all. When pressing brake pedal, I hear hissing sound coming from where brake pedal is. The idle increases too. When I let go of brake, no more hissing sound and idle back to normal. When trying to stop pedal feels spongy and the car does stop, but feel have to apply more pressure to brake.

About to order new brake booster, as I think that is the problem. When searching, some boosters say "without abs". So i assume there are ones with abs. How would i know which one to get? Silly question, sorry.

 

I had the same issue on an 87. This fixed it for me. The rear brakes were WAY out of adjustment. I adjusted those. The pedal stopped feeling soft and the travel of the brake pedal decreased ALOT. Stopping feel was more confident. Secondly, there is a small foam filter on firewall, inside the cabin, on the brake booster. This foam filter is supposed to quite down the hissing of the air going into the booster. Mine fell to pieces in my hand. So that added to the hiss volume. But, with the decreases brake pedal travel, my hissing is virtually un noticable now.

The only difference is it did not affect my idle, so you may have a different situation.

 

So what year is it?
to answer your question: depends on what you have now but from what I know, unless '00 and '01' 's have them, xjs didn't have abs.

Likely vacuum loss; lots of info on this and how
you can check the booster more specifically

 

It's a 91 cherokee xj, 4x4, 6 inline

 

I understand sometimes you just need to fix the issue and spending any more than that isn't in the cards.

On the other hand, one of the best upgrades you can make to a early-model XJ is the dual-diaphragm brake booster. Night and day difference, going from an old 70s pickup truck to a modern vehicle.

A kit is available to make things easy

https://www.quadratec.com/p/omix-ada...ep-cherokee-xj

or, if you can fabricate the 1/4" spacer, visible in the first picture between the white foam gasket and the brake booster, you can buy parts separately and save some money. The large diameter hole in the middle is the PITA. It's just parts off a 95-96 XJ, so the JY is an option...

 

I looked where this abs supposedly goes, tonthe right hand side of brake pedal, but don't see anything there but the alarm system. There is an abs relay; would that necessarily mean it has an abs?

 

At the top of the first picture of the below, you can see the master cylinder and the rod sticking out of the brake booster. As you can see, it'll be pretty obvious with all that under the hood.

The general consensus is that this early system is a disaster waiting to happen and you're better off eliminating it than fixing it. Eliminating it is as easy as running steel lines directly from the master cylinder to the proportioning valve directly below it.

 

Hello thank you for reply. But is there supposed to be a picture of something or to see if car is equipped with abs?

 

That would help, wouldn't it? DOH !!!

https://www.ebay.com/itm/404347773064

 

Oh, ok. Yeah mine looks nothing like that. But mine is not a bandix system eitther. So, if i had an abs system on mine i woould be able to tell by looking at master cylinder/brake booster assembly? On mine, its just a simple master cylinder with two lines. Also, the brake booster and these two are attached to each other. I want to order the booster and fouond one for $84 at parts geek but it says only for cars without abs. So i just want to make sure i dont have abs system.

 

These are pics of my booster and master cylinder....certainly doesn't appear to be equipped with abs, huh?

 

Yup, no ABS...