• Hey Guest!
    British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
  • When posting a classified ad, you MUST select a prefix from the drop-down next to the subject line. If you don't you will get an error and your ad will not be posted!
Tips
Tips

Master Cylinder Seal Question

Share this page

J

jjscott

Senior Member
Offline
I am rebuilding the drum brake dual master cylinder with the Moss kit (180-970). The main seals and washers fit the bores correctly. The secondary seal is to be stretched over the piston and then slid into the bore.

The pictures show the seal over the piston; I believe it is properly seated. The diameter is a good 1/32" greater than the bore. Do I just force it into the bore? I am afraid it will be so tight the spring won't return the piston. Have I done something wrong?

Jim
 

Attachments

  • IMG_0204.JPG
    IMG_0204.JPG
    155.9 KB · Views: 97
  • IMG_0205.JPG
    IMG_0205.JPG
    185.1 KB · Views: 83
Jim, i believe you have the seal on backward's. If you fit it the other ways around and lube it with a little brake fluid I don't believe you will have any problem's.

Kurt.
 
Problem Solved:

I pulled the seal back toward the center. Pulling it back revealed that the lip on the rear side had been rolled under and preventing the seal from fully seating in the groove in the piston. It wasn't on backwards, it was just on wrong. Thanks, Kurt, your post made me move the seal and disclose the real problem.

Picture correctly installed.

Jim
 

Attachments

  • IMG_0216.jpg
    IMG_0216.jpg
    87 KB · Views: 93
That looks right, Jim. Should work fine now.

Kurt.
 
And it should be a bit of a snug fit in the bore, remember its pushing against the fluid and keeping it from running out the pushrod end of the master. Too loose and you get leaks.
 
Back
Top