p5 brake swap

[Damkid]

Yup I gotta agree with Gomez as well, ive had a few MC's go bad on me and it's a pain to diagnose lol

[Gomez]

Ok after the line in the res bleeding trick I still saw bubbles. So I got pissed, went into the car and pumped the holy crap out of it for 10 seconds. looked in the res to see the fluid went from clear to mud. OK, time to pull the m/c off and I see oil "fall" out of the space between the mc and booster. There was loads of the same color fluid. Problem solved. The plunger (correct term?) has a bad seal. Like my buddy said, "lots of things can happen when they go dry". Welp, i'm off to the jy in about 5 minutes. Going to make sure there is brake pressure in the lines from the Festy I pick so I don't buy a dry one. lol at my luck

[Gomez]

$6 jy mc fixed my problem. I really hope that it may work for you Paul.

[neanderpaul]

Thanks, I'm going back for round 3 in a few minutes.

[neanderpaul]

First we tried to use the pump/vacuum as a vacuum. Then we tried the hose on the bleeder into the bottle method. Pumped until there were no bubbles. I am in doubt that a good mc at the start of this swap went bad. We are getting a donor p5 however on saturday. may try that mc. I am also wondering if the bore is different enough to cause our problem. The brakes barely work. Sometimes they don't work at all. they can be pumped up a tiny bit. Called mazda peed. No help there. called the mazda dealer. No help there. Called advance they said the 6 mc and the p5 mc look totally different. I am officially frustrated.

[Damkid]

I can't see the bore size being the problem, if all seals are good and there's no air, then the P5 mc will still put pressure in the lines to make the brakes work

Have you guys at least unbolted the p5 mc from the brake booster to see if there's any fluid leaking into the brake booster?

[neanderpaul]

I can't see the bore size being the problem, if all seals are good and there's no air, then the P5 mc will still put pressure in the lines to make the brakes work

Thank you. Good info. we needed that.

Have you guys at least unbolted the p5 mc from the brake booster to see if there's any fluid leaking into the brake booster?

No. We can do that next.

[Damkid]

No prob Paul, it seems like you guys are at the point where any tips to help diagnose the problem will help.......

On my 300zx when I first got it, the mc would leak into the brake booster but only when It got cold out, the first summer, no issues, first winter, leaked out all the fluid even though it was parked all winter, came spring, bled the brakes, found no leaks and drove it all summer and come winter again it started leaking again

So mc's can act really strange when they go bad lol

[Gomez]

So mc's can act really strange when they go bad lol

I had one that actually ordered a pizza in my name on my moms card. lol

Seriously though, if you were able to bleed all of the air out with the hoses into the bottle method, i'm kinda with ya Paul, it doesn't sound bad.

Is it possible that there is a huge air pocket inside the mc's that is not going through the bleeders because the air is above the bleeder screw? You might have to bench bleed the calipers too. idk just a physics idea

[Justin2129]

took it to firestone to have the brakes bled. when they looked at it, they said that, because the bleeder screws point down on the rear calipers, air was probably getting trapped in them.

I'm going to unbolt the calipers an bleed them with the bleeder screws up, then just put them back how they were. hopefully that will do the trick!

[Damkid]

Good luck :thumbright:

[neanderpaul]

The garage he took it to said the problem is that the bleeders point straight down. The new plan is to remove and rotate the calipers, bleed and replace. I am sick of bleeding brakes.

[Justin2129]

I am sick of bleeding brakes.

+1 after this it's going to the shop for them to do

[Damkid]

Is it possible that the calipers are on the wrong side? i remember hofficergrover had his front calipers of wrong (pass. side on the drivers hub etc.) they bolted up just fine but the flex line wouldn't reach since they weren't on right

Just another thought for you guys to check out

[Justin2129]

what's the flex line? (sorry im new at this haha) we put them on as they were marked, plus the way they are is the best way to get the e-brake to hook up right