Master cylinder diy?

215kid · #1 06-03-2013, 05:03 PM

Is there a master cyclinder diy floating around anywhere? I tried searching but didn't find anything. Is it hard to do? I can't imagine it to be. I had a leak on my driver side behind my front tire and in front of my rear tire. I took it to an indy to fix my door which turned out to be the lock actuator. They fluched the fluid because they said there was red fluid when they went to bleed the brakes. 2 liters to flush and bleed? And was charged over 550 to fix the door and flush the brake fluid. They said the master cylinder needs to be changed. Does that sound right for a leak? Any help would be appreciated but I don't think that the same shop will be doing any other further work.

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X5SND · #2 06-03-2013, 05:53 PM

I don't recall one off hand.... It looks to be fairly accessable, so it shouldnt be that big of a job. The only complication I could possibly foresee in a MC replacement is if you manage to get air into the abs valving. If memory serves me correctly you need a GT1 to bleed it.

2 liters is a fair amount to use, but then again if it's never been flushed prior in the life of the vehicle (which surprisingly enough, isn't that uncommon), it sounds about right.

Did they mention why the MC needs to be changed? Normally it's the lines that leak...

Doru · #3 06-03-2013, 06:12 PM

Here's a generic master cylinder seal repair DIY. As mentioned above, you will need access to a GT1 to cycle the ABS unit. As far as I see it, the most difficult chore would be to find the correct parts (seals) and a GT1. The master cylinder is very easy accessible. If you attempt doing it yourself, make sure you don't spill that paint remover of brake fluid on the car's paintwork.

bcredliner · #4 06-03-2013, 06:13 PM

The master cylinder can leak, however, brake fluid leaks behind the front wheel and in front of the rear wheel would not be associated with the master cylinder. I would check the lines into the brake calipers or see if the fluid is leaking out of the calipers which would indicate a brake piston seal is bad. If the X is running and you continue to push hard on the brake pedal will it go to the floor?

215kid · #5 06-03-2013, 08:17 PM

Well when I picked up the car tonite, I was told that the brake lines were fiked and that it doesn't leak anymore. I will be monitoring that closely. The brake pedal is super soft until the bottom so there is definitly an issue there. The shop also told me that they believe someone had put transmission fluid in the brake fluid because when they went to bleed it, red fluid came out. I know that once the is started leaking I put a bottle of DOT4 brake fluid and it was clear. That could have been the reason for the master cyclinder going? I

JCL · #6 06-03-2013, 09:54 PM

Leak was more likely brake lines than the master cylinder. Master cylinder leaks are often between the two circuits, ie an internal bypass, not to external.

Brake fluids are available in red. Marketing. Just like the blue one. A different colour does help when flushing it, but it is mainly marketing.

bcredliner · #7 06-03-2013, 10:49 PM

If the leaks are fixed and you have a "soft" brake pedal I would have the brakes pressure bled to see if that corrects the problem. They may not have done so when they worked on the lines. Test the brakes stopping from highway speed and see if you feel the pedal fade or it feels normal. You won't have to see a leak if there still is one, the fluid level will tell you.

bcredliner · #8 06-03-2013, 10:56 PM

I think it was good to change the brake fluid. If you didn't know what it was and you had a leak, no better time to flush the system.

Doru · #9 06-03-2013, 11:21 PM

If someone put something different than the Dot4 fluid in the system, you WANT to flush everything out. I am not sure the shop that serviced your car has a GT1 to cycle the ABS, but you NEED to cycle it, because the fluid trapped in there WILL NOT be cycled/flushed otherwise. Your life & safety depends on your brakes. I would either find a trustworthy indy with the right tools, or at the last resort, I would go to the dealer and explain the situation, so they have the junk flushed out of the ABS.
The brake pedal should not be soft.

JCL · #10 06-04-2013, 01:40 AM

Probably time to find another shop.

They don't know that brake fluid comes in crimson red. OK, so maybe they don't sell that type.

They can't tell the difference between a hydraulic fluid (oil) and brake fluid. Just need to rub it between your fingers to feel the difference.

They appear to have left air in the system. May be due to air in the ABS controller, may just be a poor job of bleeding it.

OP, if you trust them, ask them to bleed it again to firm up the pedal. If you don't, go to another shop with the same request.

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