• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
master cylinder leaks
#1
I recently replaced the front disc brakes (pads/calibers/rubber lines).  I use DOT 3 fluid to refill/bleed.  Is this the correct fluid?  I now have a leak between master cylinder and booster, also i have fluid inside booster.  It leaks just sitting still.  Brakes work fine when reservoir is full.  
I'm leaning toward replacing the master cylinder.  Is there a seal on booster that needs replacing too.
thanks
Bob
  Reply
#2
Definitely want to replace that ASAP. Brake fluid is no good for the booster and will ruin it.

DOT 3 is the correct fluid.


  Reply
#3
(04-30-2020, 11:08 AM)Hemikiller Wrote: Definitely want to replace that ASAP. Brake fluid is no good for the booster and will ruin it.

DOT 3 is the correct fluid.
can booster be drained without removing from car.  I stuck a wire down in the vacuum line hole and it showed fluid.
  Reply
#4
More than likely from bleeding the brakes it damaged the plunger. Rust gets in the cylinder and then when you bleed the brakes, the plunger travels further down the cylinder and hits where the rust forms. This can damage the plunger and makes it leak. It’s easier to replace the master cylinder than to try to fix the existing one. This same thing happened to me last year.

run_horse Run Horse Run!
John 72 Q Code
  Reply
#5
The brake fluid will kill the booster. Go to the WCCC West Coast Cougar Classic web site they have a video on the boosters. They go to the old Booster Dewey shop now Booster Steve I think. 
The brake fluid eats paint off the booster and will destroy your rag joint on the steering shaft. 
To get the fluid out of the booster you have to take apart. I built a fixture to hold the can while reversing the crimps around the outside. Inside there is not much. Diaphragm, rod with a seal, Bakelite part that diaphragm fits on and big cone spring. The check valve on the booster can be checked by blowing into it. See on the video on WCCC. 
I have not found a supplier for new replacement parts for the booster.
You can get a replacement cartridge for the master cylinder. There is a allen button head screw in the bottom you take out and remove the snap ring and scrape the rust out of the bore. Put air pressure on front port and it should blow the piston out. You can get a brake hone and clear the rust.
The parts house masters are not exact in shape as Ford if you want original keep yours. It should be 15/16" dia. and drum was 1" dia. The setting of the rod length is critical on install in the booster see the Ford manual has to be set correct to work correct.


When a man is in the woods and talks and no women are there is he still wrong??
Tongue
David
  Reply
#6
As luck would have it I found a supplier for the brake booster rebuilds. So I will probably beef up my fixture some and see how it goes. Need some new molasses to clean the rust off also. 
The cost they gave to me is diaphragm $25.00, seal between master and booster, $6.00, Firewall seal $5.00 and the rod boot is $6.00. Check valve an seal is also around $5.00.
Probably going to order enough to do 4 tomorrow. I need two for me and will see how it goes might start rebuilding them. I need another project, lol.


When a man is in the woods and talks and no women are there is he still wrong??
Tongue
David
  Reply
#7
(04-30-2020, 01:31 PM)Carolina_Mountain_Mustangs Wrote: As luck would have it I found a supplier for the brake booster rebuilds. So I will probably beef up my fixture some and see how it goes. Need some new molasses to clean the rust off also. 
The cost they gave to me is diaphragm $25.00, seal between master and booster, $6.00, Firewall seal $5.00 and the rod boot is $6.00. Check valve an seal is also around $5.00.
Probably going to order enough to do 4 tomorrow. I need two for me and will see how it goes might start rebuilding them. I need another project, lol.
Thanks for the info, let me know how your rebuild goes.
Bob
  Reply
#8
I need the 2 wire plug for the brake pressure switch. I can't find any vendor who has it, did found the switch.
Bob
  Reply
#9
(05-10-2020, 08:34 AM)rjpohl Wrote: I need the 2 wire plug for the brake pressure switch.  I can't find any vendor who has it, did found the switch.
Bob
I got lots of those.

Let me check your shorts!
http://midlifeharness.com

[Image: Flamicon2.jpg]


[Image: oldfart.png]
  Reply
#10
I'd like to replace seal on the brake booster push rod (master cylinder side). I checked a few vendors and didn't see this seal. Any idea where to get it?
thanks
Bob
  Reply
Share Thread:  


Possibly Related Threads…
Thread Author Replies Views Last Post
  Anyone here use Master Power Brake Kits? 73' mach 1 3 440 12-02-2019, 07:09 PM
Last Post: pedstagn71
  Paint Master Cylinder to prevent rusting jowens1126 21 1,006 10-11-2019, 09:23 PM
Last Post: jowens1126
  Master cylinder leaks from behind after fluid change IstoT 6 787 07-12-2019, 12:26 AM
Last Post: IstoT
  Wilwood master cylinder tony-muscle 26 1,451 12-11-2018, 11:42 AM
Last Post: Tnfastbk
  73 Master cylinder/brake booster combo LOUHABY 10 1,297 08-16-2018, 10:06 AM
Last Post: Carolina_Mountain_Mustangs



Users browsing this thread: 1 Guest(s)