90 Cherokee Power Brake Booster vac leak

[pomerom]

My 90 Cherokee has suddenly began developing what appears to be a vacuum leak in the booster module.

Can hear it mostly from inside the vehicle, but also with an ear close to the module.

Happens when the peddle is pressed during braking; only after some force is applied and stops when additional force happens -- that is, it happens during about the middle of the peddle movement.

I have the shop manual and have read in it what is required to replace this booster. I can see that some of it must be done under the dash/floorboard area; some of it around the master cylinder.

It does not appear to be technically difficult -- is that correct??

What I can't tell for sure from this reading is -- how big a job is this really? Is this something that is 'a bear' because of the locations of working inside on the floorboard? Or is it something that can be done with just a little persistence. I'm not, I'm afraid, the most agile of people ....

I have a quote for around $160 parts and $150 labor from a trusted mechanic. Is it worth that rather than taking it on myself??

I've owned it since new in 1990 and it hasn't been in the shop yet -- wondering about this one.

Any thoughts and suggestions will be most appreciated ....

Mike

 

[XJING]

Its not too bad to swap out the booster and master cylinder, Do you have ABS. If so I dont know how hard that would be.. but if its not its pretty easy to do and the underside of the dash stuff is just taking the rod off the pedal. everything else is under the hood. I dont know if the 90 has a single or dual diaphram booster, Most with a single diaphram booster upgrade to a '95-96 dual diaphram booster to help the stopping power. but if you are going to put in another single booster and master cylinder, its pretty much plug and play... Good Luck....

 

[BIGSLVRXJ]

Its not too bad to swap out the booster and master cylinder, Do you have ABS. If so I dont know how hard that would be.. but if its not its pretty easy to do and the underside of the dash stuff is just taking the rod off the pedal. everything else is under the hood. I dont know if the 90 has a single or dual diaphram booster, Most with a single diaphram booster upgrade to a '95-96 dual diaphram booster to help the stopping power. but if you are going to put in another single booster and master cylinder, its pretty much plug and play... Good Luck....

You don't have to swap the master at the same time unless you're going to a dual diaphragm setup. Your 90 as well as mine is a single diaphragm booster (mine leaks too). I intend to do a swap to the dual diaphragm shortly which involves a new master at the same time. For yours though a direct replacement would just mean unbolting the master cylinder in the engine bay from it, setting that aside, and undoing the rod and 4 nuts from the inside under the dash. It's a pretty easy job, definitely not worth 150 in labor...jaysus.

 

[KsMJ]

I did this to one of my Comanche's. Paid like $78 for a rebuilt booster at O'Reilly's, so you can really save some coin. It's aggravating, anything under the dash is, but not as bad as coming up with more money. The only problem I had, as I recall, is the the the brake lines wouldn't allow the m/c to clear the booster without a little bending, but I was able to get it to clear. Be careful of breaking a line or loosening any connections. Good luck!

I might add that I chose to remove the lower kick panel of the dash for better access.

 

[XJING]

You don't have to swap the master at the same time unless you're going to a dual diaphragm setup. Your 90 as well as mine is a single diaphragm booster (mine leaks too). I intend to do a swap to the dual diaphragm shortly which involves a new master at the same time. For yours though a direct replacement would just mean unbolting the master cylinder in the engine bay from it, setting that aside, and undoing the rod and 4 nuts from the inside under the dash. It's a pretty easy job, definitely not worth 150 in labor...jaysus.

I guess I didnt make that very clear... about not having to swap masters. Thanks for clearing that up to the OP

 

[BIGSLVRXJ]

I guess I didnt make that very clear... about not having to swap masters. Thanks for clearing that up to the OP

No that's fine, I just didn't know if he was like me trying to put off learning how to bleed the brake system. I'm trying to hold off having to learn that as long as I can.

 

[pomerom]

OK -- I appreciate and shall take the consistant advice.

I do know how to bleed brakes and used to be a 'mechanic' long before mechanics became 'technicians'. Its just that some physical issues cause me problems when trying to get down under the dash.

But I do have a friend -- which is always a good thing -- and he can help me with that part.

So I'm going to go for it myself .. any more suggestions or 'gotchas'??

Thanks .....

Mike