# Brakes failed after rear brake replacement **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [July 28, 2016, 10:04pm UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123 "2016-07-28T22:04:15Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [July 31, 2016, 1:59am UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123/21 "2016-07-31T01:59:19Z")
My memory’s a little foggy . . . Are you the guy that works at Autozone . . . ? Please forgive me if I just insulted the heck out of you 🙍 If you are that guy, does Autozone still have some kind of “spokesperson” on TV ads . . . I can’t recall seeing Jesse James promoting the brand, lately. I’m assuming he’s “too good” for that now ---
**Author:** ![NYBo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nybo/32/17281_2.png) [@NYBo](https://community.cartalk.com/u/NYBo)\ **Post date:** [July 31, 2016, 2:07am UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123/22 "2016-07-31T02:07:43Z")
[quote=“db4690, post:21, topic:94123, full:true”] My memory’s a little foggy . . . Are you the guy that works at Autozone . . . ? Please forgive me if I just insulted the heck out of you 🙍 If you are that guy, does Autozone still have some kind of “spokesperson” on TV ads . . . I can’t recall seeing Jesse James promoting the brand, lately. I’m assuming he’s “too good” for that now [/quote]Yes, that’s me, in my retirement job. No insult taken. I don’t recall seeing any AutoZone commercials recently. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [August 1, 2016, 2:30am UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123/23 "2016-08-01T02:30:18Z")
I agree with the Master Cylinder (MC) as #1 on the candidate list. I also urge you to please seek out a reputable independently owned and operated shop and have the car towed there. **This vehicle is unsafe to drive.** For some reason that I don’t understand, many new car dealerships seem disinteresting in doing serious diagnosis on old vehicles. We’ve discussed this among ourselves here on the website, and I still don’t understand it. But whether I’m right or wrong, this dealer clearly isn’t doing the job for you and is allowing you to drive away with a vehicle that could get you killed. Please, I urge you, **have the car towed** to another shop. By the way, an independent will likely save you lots of cash too. Dealerships typically charge more for parts and for labor. ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [August 1, 2016, 2:34pm UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123/24 "2016-08-01T14:34:47Z")
> [@Roger124](#): > > When the master cylinder gives out like that. Would it be possible to get some braking back by pumping it? Hit the brake pedal hard and fast. The MC is kind of like a syringe. A syringe has a rubber-sealed plunger that pushes fluid out of the needle. If you get something between the rubber seal and the syringe wall, you’ll get fluid leaking past the seal and behind the plunger instead of going out through the needle. If you have a leaky MC seal, then hitting the brake fast doesn’t give the fluid time to leak past the seal before you get some braking pressure. Needless to say, this is what to do if you discover that you’ve just borrowed a car with a leaky MC. If you _know_ your MC is leaky, it should not be driven until it’s fixed. > [@Siena1383](#): > > To clear one thing up, the brakes did NOT fail the first time I used them. That isn’t unusual. It can sometimes take time for the gunk the piston picks up to get bunched up under the seal and cause a leak. Also adding another “for the record” that I’ve had several MCs go out on me and friends over the years, and they’ve never caused the brake light to turn on. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [August 1, 2016, 2:52pm UTC](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123/25 "2016-08-01T14:52:05Z")
Excellent added point, shadow. The brake warning light (not the ABS light) reacts to a float sensor in the brake fluid reservoir. Since fluid passing by the seals in the MC pistons moves between the pistons internally and never reduces the fluid level in the reservoir, the light never illuminates. The float has no way of knowing fluid is passing the pistons internal to the MC. [Previous page](https://community.cartalk.com/t/brakes-failed-after-rear-brake-replacement/94123.md?page=1)