# 66 LeMans - "Mushy Brakes"



## LeMansChaser (Mar 13, 2012)

On to the next project. 66 LeMans, MostlyOrg, Org326, Org4Speed, Hardtop. 

I recently changed out the body mounts on the car to keep the yoke from knocking on the tunnel. Since that project the brakes have gotten progressively worse (over two short drives), I press them down hard and they feel mushy. Now I have to press them all the way to the floor to get ANY response. Needless to say it is DANGEROUS and cannot be driven as is. 

I was careful to not pinch anything when I lowered the car after changing the body mounts. This evening I climbed back under the car and traced all the lines. The rear brake cables leading back appear to have not moved from there previous position, they are tight and intact. The lines on the front breaks also appear to be intact and no pinches (that I can find). There also appears to be NO leaks from the front break lines (there are other leaks that will be tackled after the breaks). 

Finally, the emergency break works well and accurately. Any thoughts... As Always, THANKS.


----------



## ALKYGTO (Mar 29, 2010)

Sounds like air in the lines. If your brake lines are old they may have cracked when moving the body around. Look for moisture on all your steel brake lines. Have you tried bleeding the system out? 

E brake (or parking brake lol) is mechanical and really has nothing to do with the hydraulic brake system.


----------



## facn8me (Jul 30, 2011)

Very good chance the master cylinder has gone out also. Check for air in system by bleeding. If you have no leaks and there's no air that only leaves the M/C


----------



## LeMansChaser (Mar 13, 2012)

Thanks every one. I will keep you posted.


----------



## 68GTO4004Spd (Jun 19, 2008)

You might have blown out a wheel cylinder, take the drums off and have a look in there. How old is the brake fluid? Brake fluid will absorb moisture over time and break down, if it's been more than 10 years, change it out. Don't want to wad up your car because of bad brakes and cheap fluid.


----------



## geeteeohguy (Feb 2, 2008)

All sound advice. Spongy pedal means air in the system or an internally leaking hydraulic component like a master cylinder. Brake fluid is not compressable. A lot of master cylinders fail internally, causing bypassing and low/spongy/no pedal. No external fluid leaks will be present.


----------



## ALKYGTO (Mar 29, 2010)

I replaced my MC last year when the pedal was spongy. It had maybe 1000 miles on it but just went bad from sitting I presume. I replaced it with a Wilwood unit (bolted on) but a stock replacement would have worked fine. Do you have a dual pot or are you still running the single? If you are changing out and not worried about "show points" I would consider upgrading to the dual MC. They are reletively cheap and a lot safer IMO. :cheers


----------



## LeMansChaser (Mar 13, 2012)

I will take this bad boy one step at a time. Tomorrow evening I will first yank the wheels/drums and inspect the internals. Then I will replace the brake fluid. I just purchased the car and I am not sure how old the existing brake fluid is so that isn't a bad idea either way. If that doesn't solve the issue I will replace the MC. The car is mostly original so I would probably purchase a new dual MC and a rebuild kit so I can keep the original parts with the car and in working order but at the same time keep the car safe. 

66GTO you said it best I sure don't want to wad up my car. 

thanks everyone!


----------



## danthepontiacman (Jul 5, 2008)

the manual drums in my 66 had got bad so i replaced all 4 original drums, put new shoes on it, replaced all 4 wheel cylinders and replaced all the hardware useing a front and back hardware kit, all of it was like $360, done great for a year then it got were the peddle went to the floor befor it done anything, i rebult the master cylinder for around $40 and been doing great since, id just rebuild all 4 brakes cuz its one thing you got to have!


----------



## LeMansChaser (Mar 13, 2012)

So my project was a little delayed (life, gezzz). Yesterday I went to inspect the brakes and they physically look good. I pulled the top off the master cylinder and it was really low and was really dirty. I cleaned it out and added more fluid knowing i was going to completely flush the system. I started on the rear passenger side and it went great, it was quick and I was able to flush all the old fluid. 

Now for the rest. The rear diver side I could turned but got NO fluid. The two fronts, I couldn't even get turned, I tried a couple different things but no dice. 

Any ideas???


----------



## ALKYGTO (Mar 29, 2010)

So you just topped off the MC and then flushed the dirty fluid through your system?

I would rebuild or replace the front or all of the wheel cylinders to start.

Is the brake light on? Your distribution valve may have shifted shutting off fluid to the rear or the line may be clogged or have a hole in it. The original lines on my 69 were rusted through where the clamps hold the line on the frame rail. I replaced them all with stainless.


----------



## LeMansChaser (Mar 13, 2012)

Thanks ALKTGTO, No, no break light. I actually cleaned the fluid out of the master cylinder, replaced it with new fluid and completely flushed the system. (To get the valves loss I taped them up real tight and applied some BP Blaster to the base, they freed right up.) In hind sight I think I would have tried a reverse flush. The breaks firmed up immediately and appear to be holding. I will continue to watch it to make sure I don't have hole in the line or leak. I did do an extremely through investigation of all of the lines and they were not rusted and all appeared to be in great shape. 

With that said I do want to at very least rebuild the brake cylinders, if not replace them all together; that however, is a project for another weekend...


----------

