# Leak from rear of new master cylnder **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [February 28, 2017, 2:15am UTC](https://community.cartalk.com/t/leak-from-rear-of-new-master-cylnder/100561 "2017-02-28T02:15:44Z")\ **Posts on this page:** 2\ **Page:** 3
**Author:** ![Jack-Dak87](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@Jack-Dak87](https://community.cartalk.com/u/Jack-Dak87)\ **Post date:** [March 2, 2017, 11:30pm UTC](https://community.cartalk.com/t/leak-from-rear-of-new-master-cylnder/100561/41 "2017-03-02T23:30:52Z")
> [@insightful](#): > > Once the pedal was “good” a few weeks after I installed a new master cylinder it stayed that way for years (until traded). I concluded the seals “wore in” and started sealing like they were supposed to. That is the same conclusion I arrived at. Nothing else explains the behavior. I took the truck out again today and there was no pedal sinkage. For the present, it ain’t broke and I ain’t gonna fix it. > [@Rod\_Knox](#): > > run the adjuster star until the shoes begin to drag on the drum, then pound repeatedly on the brake pedal to shift the shoes to their most centered location and then running the shoes out further if they no longer drag Did as you suggested RK and adjusted until pounding the brakes no longer loosen the slight drag. > [@Rod\_Knox](#): > > How high is the pedal? On second reading, not quite sure what you mean by that, but the the face of the pedal is 5 1/2 inches from the floor at rest and 3 1/2 inches when the brakes engage. That seemed like quite a bit when I measured it, but it feels much higher at the engage point than before the shoes, master and wheel cylinders were replaced and the system bled and the brakes manually adjusted. I am assuming at this point that the self-adjusting mechanisms haven’t been doing their job, which, from my google searches, is not entirely uncommon. I’m will be keeping my eye on the top of the plastic rez on the MC to see if it continues to leak from the caps. Heart-felt thanks to all for the feedback. Jack ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [March 3, 2017, 2:02am UTC](https://community.cartalk.com/t/leak-from-rear-of-new-master-cylnder/100561/42 "2017-03-03T02:02:47Z")
A 2 inch drop to a rock hard pedal sounds good. Now drive to a street clear of traffic and at 30 mph slam on the brakes and if the car comes to a straight stop do the same panic stop at 45 mph. If everything feels good drive a few blocks and then check the wheels to see if one of the brakes is heating up. If not and the brake fluid levels has not changed you’re likely in good shape. [Previous page](https://community.cartalk.com/t/leak-from-rear-of-new-master-cylnder/100561.md?page=2)