Aftermarket brake master cylinder? Install?

Hello all, I needed some information. About 9 months ago, I replaced my truck's brake booster and master cylinder as there was a major pressure loss on the brake pedal. I went with OEM parts and ran synthetic brake fluid and had it professionally installed. Worked great. Now, I'm almost positive the master cylinder is bad again. Unfortunately, I don't have the time or money to go with another OEM one because it takes 3 days for the dealer to get it. I'm planning on getting a new one from my job made by Motorcar Parts of America. Does anyone run one? I know the duralast master cylinders from AutoZone suck. Also, how difficult is it to replace and bleed the brakes? I bought a really nice one man brake bleeder kit and the master cylinder doesn't look too horrible to replace but I've never done it before and would like to save some $ if I can. I have the tools for the most part and will attempt to do it myself if its not too bad. Thanks in advance

 

I’m not sure if you can do the mc without getting air in the abs. Once that happens no amount of bleeding will get it out.

What symptoms is leading you to believe it needs replacing?

 

Air in the abs? And I'm basically having the same symptoms I had before when it was bad. Longer brake times, pedal to the floor, and I've noticed that when my foot is on the pedal it wants to creep forward some.

 

If you properly bench bleed the new master cylinder and then bleed the lines at the master cylinder after you install it there should be very little to no air left in the system, any that is left can be bled out at the wheels.
Now if you have the hydraulic booster/master cylinder/ABS assembly that is a different story and does require a scan tool to bleed properly.

 

The guy that did it last time is a pro so I trust him to do it. I'm pretty sure he bench-bled it as well but I wasn't there to see it. But he's a really good tech so I believe he did it right, just a failed part.

 

I mean if it worked fine for awhile after it was done and the brake fluid hasn't been low there's very little chance there's air in the system.
ABS units can fail in a way that will mimic a faulty master cylinder as well but it's not very common and kinda tricky to diagnose.
If the master cylinder has failed again and it was indeed an OEM unit it should still be under warranty.

 

Well, I’d say go find a dirt road and slam the brakes a few times to activate ABS, then do a good long bleed at the wheels again.

@Dm93 did you mean electric instead of hydraulic? Aren’t they all hydraulic?

 

Well I guess technically it's electro-hydraulic but I call it hydraulic, the standard booster is vacuum.

 

Well, I haven't had to add any fluid to it at all so I don't think it's the ABS module. It's been a month since I did brake work on it because I put on extended rear brake lines and stock front metal lines to the caliper and it was professionally done. I'm almost positive it's the master cylinder going bad slowly because it's almost doing everything it did last time when it failed. Just not nearly as severe. I know it's still under warranty but the problem is that this truck is my daily and the dealers local to me don't have it locally stocked and I don't have time to wait. I'm going to order the aftermarket one from my job and swap out the bad Oem one from Toyota to keep as a backup

 

Vacuum hydraulic

I know what you meant

 

MPA supplies the Duralast program....same shit.

I'd start with some diagnosis....what are the specific symptoms? Are they repeatable every time? If not, have you figure out how to make them repeat?