I'll reply to the list because, ironically, my 72B had symptoms just like
this right after its first drive in several years - it's initial drive
after major restoration work. So I figured since the front brakes were both
locking, it must be the master cylinder. Rebuilt that, same problem. But
the rear wheel cylinders, when bleeding, did not seem to bleed quite right
- the flow seemed reduced. So I rebuilt the rear wheel cylinders. Somewhere
in that process and trying to rebleed, I realized that the front brakes
were overheating and locking up because of the rear brakes, NOT the front
brakes. The rear brakes were essentially not engaging fully so the front
brakes were overheating, doing all the work! So now with master cylinder
and rear wheel cylinders rebuilt, I focused on getting the rear brakes to
engage as they still did not work, even after rebleeding. Finally, I
located the problem but only by having someone pump up the brakes - turns
out there was a pin hole in one of the rear metal brake lines. Small enough
that I couldn't get it to expell any brake fluid until the system was
really pumped up, but apparently it was allowing air into the system.
So I would suspect a similar problem with your Jeep. But the solution may
be in replacing parts until the problem is fixed - but I'd think the
lines/hydraulics/master-wheel cylinders are the places to start. Jack the
rear up and see if the brakes actually stop movement of the rear wheels.
David Councill
67 BGT
72 B
At 07:57 AM 5/31/2003 -0700, Paul M. wrote:
>I apologize for the lack of MG content with this post,
>but I am desperate, and need the help of the combined
>technical minds on this list. Please reply off
>list...
>
>I took my wife's 1999 Jeep Grand Cherokee in to a
>"bargain" brake place to have the brake pads replaced.
> They replaced them on the front and rear. As far as
>I know, no other work was done.
>
>After leaving the shop, within about a mile, the front
>brakes were clearly dragging. It started off not too
>bad, and got progressively worse and worse. I knew
>something was wrong as was trying to limp it to a
>"real" service facility, when the Jeep basically
>became undriveable. The front brakes were essentially
>locking quite seriously and generating a LOT of heat.
>So I pulled it over and called the brake place that
>did the original work. They said to take it wherever
>I wanted and they would stand behind it.
>
>The shop I took it to - after two days of digging -
>says they are totally stumped and doesn't know what
>the problem is. The rear brakes are fine. BOTH front
>calipers are locking up. When they cool off
>completely, they free up quite a bit - enough to drive
>- but after a short while, they start dragging more
>and more and more until eventually you can't turn the
>wheels at all. Their "solution" is to replace
>virtually everything. Calipers, rotors, lines, and
>possibly the master cylinder. I am not comfortable
>with throwing parts at this thing without knowing
>what's wrong, and since they don't know what's wrong,
>the original brake place is angling to NOT pay for any
>resulting damage, saying that it appears to be a big
>coincidence.
>
>So I took it out of the second shop and towed it to
>the Jeep dealer, thinking they could get to the bottom
>of it. But after a day of looking they appear to be
>totally stumped too. Everyone who looks at it says:
>"There doesn't appear to be anything obviously wrong,
>and we have never encountered anything like this
>before."
>
>Any thoughts? I DO NOT want to get stuck replacing
>the whole brake system just in the hopes of fixing the
>problem without knowing what it is. Plus, I need to
>know what caused the problem so I can know whether or
>not the "bargain" brake place was at fault in any way.
>
>I'm desperate.
>
>In summary, the facts are these:
>
>1) The front brakes started locking literally less
>than a mile after leaving a shop that changed the
>brake pads front and rear. Nothing else was changed.
>
>2) I never lost the pedal or got any kind of ABS
>warning light or anything.
>
>3) The rear brakes are fine. The wheels turn freely
>at all times, and the brakes work fine back there.
>
>Again, sorry for the lack of MG content, but I don't
>know what to do. Although I DO find it amusing that
>my MGB is now our only car, and it has been the
>reliable old workhorse through all of this... :)
>
>Thanks in advance,
>
>=====
>Paul Misencik
>1971 MGB Tourer - Blaze
>
>Huntersville, NC USA
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