You are not logged in.
Weird...
The shop that I had the Jeep towed to replaced the broken front line,
and the master cylinder. Bled the system several times, and finally got
a firm pedal. Went to pick it up yesterday, and the pedal went to the
floor immediately. I left it at the shop.
Went in this morning to talk to the manager, and they apparently had a
heck of a time getting it bled. I do have ABS, but they reconnected the
fuse that was pulled, and it made no difference. He told me to let him
have it for awhile. Whatever.
Calls me back around noon and asks for a guinea pig...gulp...okay. I
head over. Brakes seem normal (pedal that's soft, like wood, and
relatively little stopping power compared to what I'm used to driving).
All seems normal.
Talking with him upon returning - he states that they disconnected the
"brake booster switch". What is this switch? And why does it exist?
As I recall, on the old Cherokee, I could lock up the tires with full
brakes applied. On this one, I've never been able to do so, even
without ABS engaging. I'm wondering if this switch is the cause of
that. And what in the hell it's supposed to do.
Offline
I had that happen to me once after replacing a brake master on a vehicle.
Pedal went to the floor and fluid level was fine.
I replaced that new master with another and no more problems.
Not sure what year Cherokee you have, but I would suspect that remanned
master is or was no good.
I need to redo my brake system and replace the proportioning valve since my
rear brakes have been on vacation since I bought my '88 XJ. Got the parts
just need the time and energy. ;-)
The only thing I can imagine he is calling the "brake booster switch" is the
check valve that only allows vacuum/air in one direction. Unless he means
one of the switches at your brake pedal.
Just ask that mechanic! If he says you also need muffler
bearings.............run away quickly!!!! lol
Check out my Jeep Cherokee
Offline
Sounds like he disconnected the booster vacuum.
If he let you drive off that way, I'd be finding another shop!
I'd bet the master is crap and the booster is allowing your pedal to drop to the floor.
Without the booster you are not able to force it down as far.
It sounds to me like you need another master.
I've replaced more than one "rebuilt" or "new" master after initial install.
Theres enough seals and stuff in there that sometimes things get screwed up when they are built.
With any luck the shop will realize it should try another one if you push the issue.
Offline
are your brake lines running through the ABS unit, and just
have/had the fuse pulled...or did you actually bypass the ABS unit so
that no fluid flows through it? We have noticed a huge difference in
stopping power once the ABS is bypassed completely. We have gotten a bit
of a good reputation around here for disabling ABS, and our customers
love the increased braking power. Not to mention just being able to stop
at all in the snow.
Offline
Okay guys...lay off the shop. I've been using them for 10 years, they
are one of the *BEST* in this area. Not that they don't make mistakes,
but they're really, really good, and I don't think they're pulling the
wool over my eyes. I have test-driven the Jeep, and it feels like it
did before the problems started.
They have replaced the master once...if it needs replacing again,
they'll do so, but I don't think the master is at fault here. I think
it was a bleeding issue. Now, Tim's a pretty smart fellow, and said he
disconnected a *switch*. Not a hose for the vacuum booster. I've got
the wiring diagrams in the Jeep for this circuit...but...the Jeep is at
the shop, and I'm at home (haven't gotten a ride to pick it up -
tomorrow).
Anyhow, I was curious if anyone knew anything about this
system...obviously...not enough to be knowledgeable. I'm almost 100%
positive it's related to the ABS - where and how I'm not sure - and Tim
was upfront with me too - and says that he's not sure, and that he's
going to do some research on this system.
As far as ABS goes, yes, I've considered removing it entirely, and will
probably do so at some point soon. It just hasn't been that important.
The Jeep stops - in what I'd consider an average amount of time and
distance for an SUV of it's vintage, with everything functioning
properly. Please understand that my daily driver is a 2002 BMW 540i.
My brake expectations are probably a bit skewed towards the performance
side of things.
Nonetheless, this switch arouses the curiosity in me, and I'll dig
around till I figure out what it is, and what it is supposed to do.
Offline
Thanks for singling out my reply.
I was not the only one who said similar.
Why did you ask us what THEY did?
We only answered to the best of our knowledge with the question at hand.
Please don't ask for advice if you don't want answers.
Sometimes they are not the answers you want or even correct.
I'm sorry if you feel like the shop was being "picked" on.
I guess the impression I got was that it was simply a shop you used because you had to.
I did not realize you had a long term relationship with them.
Go back and ask them what switch they disconnected when you pick it up.
I also did not get the full idea or understanding that the Jeep was indeed back to what you consider to be it's normal condition.
Sometimes I wonder why I bother posting anything at anytime unless I have time to go find a manual for the exact vehicle in question and look up the system so I know exactly what is going on. Oh, yeah, I remember, I like to do this...
Offline
The only brake switch I am aware of is the one on the proportioning valve which turns on the brake light warning light on the dash. This happens when there is a fluid loss in either the front or rear of the system. Some times these need to be reset after fluid has been drained from the system. But usually the light on the dash would be on and that is why you some times remove it and bleed some fluid from the hole it came out of before replacing it again to remove any air that is giving the switch the reading of no fliud.
Offline
I'm going to reply to this. I've pondered the responses.
I think basically it boils down to this. I"m new to this forum, and I
forget that. Most of the really technical questions that I ask are not
to this group - they're to my Volvo group, where I've been a member for
over 10 years, and am regarded as one of the experts of the experts. So
if something stumps me there, it's because I'm truly stumped - or simply
have never run across that problem. By the same token, it's also known
there that I have two shops that I've worked closely with for more than
ten years, and they're who I trust with the work I don't want to do
myself, or don't have the tools to do myself.
So, I apologize for not being a bit more clear in my original post. The
response was not meant to come across as mean, nasty, hurtful, or
anything else. Quite simply, I know shops make a lot of mistakes, and
rip a lot of people off. I should have clarified in my first email that
this shop literally maintains my fleet - from the Jeep - to the BMW, to
the Volvo, and about a dozen of my friends cars, and clients cars - that
I gave up taking care of when I stopped turning wrenches for anyone but
myself. They're quite good, and quite honest. I've only had one other
"comeback" to them, and it was for one of their 16yo techies not
listening to me when I told him he couldn't rev that particular Volvo in
Park...and he chose to do so anyway...the results were not good. And
the shop wound up installing a new transmission. I don't think he was
there much longer...
Anyhow...back to the original problem.
I gave a lot of background, because I thought it was relevant.
When I picked up the vehicle the second time, everything functioned as
normal and has continued to over the past 150 miles or so that I've put
on the Jeep. So, I think the master cylinder can be discluded from
being bad, at this point.
I am still quite curious what this brake switch is, and what it's
function is. I need to take the Volvo in for service tomorrow, and I'll
talk with Tim more about it then. It seems like the list doesn't know a
whole lot about this switch, and neither does my shop. I will report
what I find, for the collective body of knowledge.
There are still a lot of little details I'm learning about on the Jeep.
I'm not nearly as intimate with them as I am the 700/900 Volvos, or the
E39 BMW's. And that's okay - sometimes I'll continue to ask stupid
questions, and I apologize for that.
I do apologize that I appear to have made some people on this forum upset
- it was not my intent with my response.
Thanks for all of the insight, and I"ll let you know what I find out, as
I discover things.
Offline
It is all good and the members here are some of the best!
Usually we are pretty thick skinned and don't get insulted too quickly, but
we will assume the same of others in this group. We try to state either the
most obvious solution or the most obscure solution , with lots of solutions
in the middle.
Sometimes people think that their toes are being stepped on when it is not
the case.
I think one time I mentioned that an employee at one of the auto parts chain
stores did not know about a part and someone on this group exploded on me
like I was talking about him. It was uncalled for and other members came to
my defense.
I think there was someone else that asked questions, was offered help and he
replied in a very negative way. ???? Again people were relatively calm there
too about that situation.
Some people just may have interpreted things wrong and given time, they can
mellow out, or leave the group.
I really don't think anyone is wrong here, now that we have all of the
information. ;-)
I still want to know about the "Brake Booster Switch" though! lol
Check out my Jeep Cherokee
Offline