Master cylinder problem?

[Rdavison39]

Hi there - I just had my front brake lines on my 1977 CJ7 replaced at a garage. Drove it home at its been sitting in the driveway for a couple of days. Went to start it up and go for a ride and when I put my foot on the brake it goes all the way and the jeep doesn't stop. I phoned the garage and they said the master cylinder has gone. If that's the case thankfully it happened in my driveway and not the road.

However, it seems suspicious. I had someone else tell me maybe there is air in the line and I should bleed it? This might make sense especially if the brake lines where just replaced.

Thoughts on this? What you think is the case....master cylinder or air in the line?

If you do suggest I bleed it, how does one go about doing that?

Are there any tests I can do to confirm one way or the other?

Thanks in advance
Ron

 

[gert]

Hi there - I just had my front brake lines on my 1977 CJ7 replaced at a garage. Drove it home at its been sitting in the driveway for a couple of days. Went to start it up and go for a ride and when I put my foot on the brake it goes all the way and the jeep doesn't stop. I phoned the garage and they said the master cylinder has gone. If that's the case thankfully it happened in my driveway and not the road.

However, it seems suspicious. I had someone else tell me maybe there is air in the line and I should bleed it? This might make sense especially if the brake lines where just replaced.

Thoughts on this? What you think is the case....master cylinder or air in the line?

If you do suggest I bleed it, how does one go about doing that?

Are there any tests I can do to confirm one way or the other?

Thanks in advance
Ron

I think that would be a yes yes and yes

yes the MC could have gone out, if it has look at the back of the MC at or on the other side of the firewall you should see wetness from brake fluid getting past the seals

It could also be the brake line connections not sealing as well, same thing check for wetness around the lines

it could also be the brakes themselves

You can try to bleed the brakes and see if it goes away but I suspect that if you had a hard pedal when you left the shop you should still have one. You have an older vehicle and it does not surprise me that you have disturbed the brake system and something else could have failed.

I really think your first stop should be the shop that did the work. Make them show you the leak at the master cylinder. and go from there. If they installed new lines and didn't get all the air out they need to finish their work.

Let us know how it goes

 

[Torxhead]

Why did you take it to the garage in the first place? If you needed brake lines, were they leaking ?

 

[hole]

Welcome Ron!
Here's a thread that may(or not ) help http://www.jeep-cj.com/forums/f19/what-proper-way-12118/?highlight=proper+brake+bleeding

 

[Posi]

If the mechanic told you over the phone it was the M/C it was an educated guess, but a guess nonetheless.

There is an easy test to confirm if you have air in your system.
Remove the M/C cover and have someone slowly pump the brakes several times. Then hold the brake down.
Have your helper slide his foot off the brake pedal so it comes up fast.
Watch the brake fluid squirt from the surface of the M/C
If the squirt is higher then 3" you have air trapped in your system.
Make sure you put towels/shop rags around the M/C and fender.
Paint doesn't like brake fluid.

Hope this helps.

 

[Rdavison39]

These are all very helpful answers. Really appreciate the feedback and patience with someone who is just trying to learn.

I don't mind fiddle-farting around with my car but one thing I don't want to take a chance on is the ability for the vehicle to stop which is why I took it to a professional to look over. He noticed some of the lines rusted so I told him to replace while he had it all apart as well he put on new calipers and pads.

I will try the last test suggested and see what happens. My instincts tell me its not the MC as it seems too much of a coincidence but we'll see what happens. I would drive the car back to the shop for the mechanic to look at and complete his work if air in the lines is indeed the problem.....but of course I can't drive it anywhere right now.

 

[Torxhead]

You could also look online for any complaints against the business to help you decide if you want to return.