Vintage Mustang Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
340 Posts
Discussion Starter #1
Working on my 68. Installed all new lines on older drums all around. Installed new master cyl. Did the bench bleed until no more air shows and then started to bleed the lines. Rear passenger was looked good after about 10 pumps but then it all fell apart. Moved to the driver rear and as I would press the pedal, fluid would leak out the bottom of the drum. I moved to the fronts and I couldn't get anything out of those but I did have fluid going up to the hoses because I noticed some drips that I had to tighten.

What am I missing? Should I open all of them and pump until I see fluid? I am thinking I have tons of air in the lines that are playing havoc with the system. As for the fluid coming off the bottom of the drum... I think I blew up that wheel cyl when pumping the brakes.

Any help would be great!
 

·
Registered
Joined
·
715 Posts
Regarding the damaged wheel cylinder, never apply brake pressure unless all of the brakes are fully assembled. Wheel cylinders and calipers need the brakes assembled in order for the pistons to remain where they belong.


As to your brake bleeding difficulty, I'll share what works well for me since I always work alone. I use a Mityvac brake bleeding kit. I've been using the same kit for many years now. I've never had an issue being able to bleed the brakes using vacuum. I'm glad I bought it.


 

·
Registered
Joined
·
8,901 Posts
Repair...???

I would replace all four wheel cylinders if I were him... If you don't know how old they are and didn't install them yourself, Change'em!

If not, You're just asking for trouble down the road.

:eek:)

Tony K.
 

·
Registered
Joined
·
233 Posts
Definitely replace them. A failed wheel cylinder almost killed me the first week I had my 66. It is the reason I upgraded the brakes to disk up front and a dual bowl master cylinder.

I was driving on the freeway and got off at my exit. I went to stop and the pedal went to the floor. Thank God the parking brake worked or who knows what would have happened.

I was able to get into a parking lot without further incident. When I did the tear down on the brakes, the rear driver wheel cylinder blew its seal and all the fluid leaked out of the master cylinder. A dual bowl master cylinder would have prevented a single point of failure.

Sent from my SM-G950U using Tapatalk
 

·
Registered
Joined
·
1,522 Posts
For about a buck more than the rebuild kit you can get quality driver level complete wheel cylinders. The shoe link pins are probably going to be pretty hammered. Unless you are building a car that needs original wheel cylinder castings you can get all brand new for less than a full restoration.
 

·
Registered
Joined
·
6,388 Posts
If you have any leak point at all in the system, you will never be able to bleed your brakes.

The lines get subjected to upwards of 1000 PSI of pressure, IIRC. So by pressing your pedal you are just shoving brake fluid out of whatever unsealed point you have, and then when you let off of the brake pedal the fluid gets sucked back up and sucks air with it. You need to seal up all leaks (replace wheel cylinders), then start with the passenger rear and only proceed to the next brake in line when there are no bubbles coming out at all.
 

·
Registered
Joined
·
4,136 Posts
I use a Motive Products pressure bleeder. Fill the MC, attach the pressure vessel and pump it up to around 15 psi. It will push fresh fluid through the lines and get all the air out. You can get them direct at www.motiveproducts.com or at Summit.
 

·
Registered
Joined
·
340 Posts
Discussion Starter #11
Thanks guys. All the brakes were assembled before trying to bleed. The cylinder that is leaking was brand new, installed that day. Maybe a crappy one. I'll replace it and see if I have better results. Also plan on getting a bleed assist tool. Eventually, going to rebuild all the brakes but I want to make sure everything is in working order first.
 

·
Registered
Joined
·
3,865 Posts
Thanks guys. All the brakes were assembled before trying to bleed. The cylinder that is leaking was brand new, installed that day. Maybe a crappy one. I'll replace it and see if I have better results. Also plan on getting a bleed assist tool. Eventually, going to rebuild all the brakes but I want to make sure everything is in working order first.


Pull it apart and see why it failed. I’d be worried there was crap in the lines from home made or fabricated brake lines. Might need to flush the system...


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
6,697 Posts
I use a 2 x 4, LOL. Been doing it this way for years. I pump the pedal up several times then wedge the 2 x 4 against the brake pedal and the seat support to hold it. Then I go and bleed the one I'm trying to bleed.
 

·
Registered
Joined
·
340 Posts
Discussion Starter #14
I pulled apart the driver rear brake and pumped a few times. Fluid was pouring out of the one side of the wheel cylinder. This is the one I just replaced. I took it back to the auto parts start and got it replaced. Hopefully better luck with this one. I assume the reason I wasn't getting anything up front is because of the leak in the rear. Will report back once I install the new cylinder.
 

·
Registered
Joined
·
340 Posts
Discussion Starter #15
Quick update - Brakes are in good working order now. I think the issue is that I had some sort of air locking issue. It took about 6 rounds of bleeding before I got all the air out. Eventually, the fronts started to burp after a few presses and then holding the pedal. Although the car is not road-worthy, I had someone give me a push and it stopped immediately after applying the brakes. Next time I'll probably get a vacuum assist bleeder to pull the air out.

I do have a brand new booster that is awaiting installation. Trying to find a used power brake pedal before I install it. Hopefully less air in the system will make the install go easier.
 
1 - 15 of 15 Posts
Top