Brake Bleed Issue

[GlanzaAtHeart]

Hey team,

As per the title, I'm having some issues bleeding my brakes. This is after installing all braideded brake lines and a new 92+ master cylinder. I have bench bled the master prior to installation.

The fronts bleed fine, however the rears, much to my frustration, won't bleed. Even after 1+ litre of fluid passing through the driver's side corner, there is still air in the fluid, and lots of it.

There is no visible leaks. I have checked for leaks and can not find any. The lines are solid and have no leaks. The brass tee next to the clutch line does also not leak and I bled this to make sure. The master does also not leak. Neither do any of the fittings in the big connection bit below the master.

The rear nipples are constantly pumping air bubbles through. I don't what it is.

Does anyone have any idea?

Cheers team.

[85AW20v]

If you're doing this with a one person bleed kit, I've found that you need to put thread tape on the bleed nipple thread, otherwise air gets sucked back in around the thread just when you think you've got it right. Otherwise it's probably a two person job, pumping up the pressure, letting it go and then tightening the nipple up before the brake is released for the next round of pumping. Jacking up the back of the car could possibly help too.

[GlanzaAtHeart]

Cheers for the input Simon, appreciate it.

Unfortunately, not only am I using 2 people, I also have the rear of the car jacked up high on jackstands....

Thanks anyway!

[85AW20v]

I just found the other day when bleeding the AW that if I opened the bleed nipple with the tube on it and had the tube above the calliper, it pretty much self bled albeit very slowly. I’ve also had success by pressurising the system from the front - basically just blew into the reservoir to get the fluid/air bubble moving along to some where it could come out.

Also - just making sure - that you’re pumping up the system, releasing the nipple and then closing it before the brake pedal is released inside the car? And that you started the whole procedure with the corner furthest from the master cylinder?

[Mr-Paulio]

I've never had the pleasure of bleeding brakes as yet.
But plenty of issues with these cars bleeding the clutch.
My only thought if you are doing everything else right is...
The rolling body had been sitting for awhile right? Many instances people have issues bleeding the clutch because the master works until it's disconnected. Perhaps worth trying to replace the master with the one from your crashed car and seeing how that goes? Also part of a process of elimination... Good luck!!

[GlanzaAtHeart]

Yeah the body was sitting for a while.

So I ended up replacing the master with another one I got, couldn't use the one from the red shell as that is an ABS one and was really different.

Brakes eventually bled with some reverse bleeding. And then some normal bleeding.

Then the pedal was still really soft when we ran the car, but if you slammed the brakes, it would lock up the rear brakes...

So then we see the fronts don't really work. Then we bled the bias valve that's there. That helped.

But now, pedal has pressure when the car is off. Then absolutely zero pressure when the car runs. A suspected booster confirmed by Carl, so gonna swap the one out of the red car.

Hopefully this is the last of my brake issues haha

[GlanzaAtHeart]

Hopefully this is the last of my brake issues haha

Hahah funny joke by me.

I removed and bench bled the master, and bench bled a couple different masters. Ended up putting it back in the car, after in bench bled perfectly, even when connected to the pedal.

I'm not sure what's going on to be completely honest.

But tomorrow i"m going to replace the bias/prop valve, the hard line, and the braided front lines just for peace of mind.

[Benckj]

When I imported my car from Japan I decided to complete a full brake rebuild including MC, calipers, braided line, etc. Like you, had multiple problems getting system to hold and finially worked out some SOB used mineral oil in the system and all rubber components had swelled. Never noticed this on the calipers but MC parts were much larger than new. The OEM kit did not include a small O ring on the shaft and this continued to cause issues. Following that hick-up the proportioning valve was buggered so that got replaced as well. After all that I had decent brakes and never caused a problem since.

[GDII]

It appears there was one major thing that was overlooked, by multiple pairs of eyes. I'll let Thomas elaborate on this when he is finished.

[GlanzaAtHeart]

It appears there was one major thing that was overlooked, by multiple pairs of eyes. I'll let Thomas elaborate on this when he is finished.

To elaborate, I've made a big 1 IQ play effectively.

Turns out, you have to put the right caliper, on the right side, and the left caliper on the left side.

After various brake masters, boosters, and replacing the front lines, Phil made me realise I had the bleed nipple on the bottom not the top. Even though he asked me to double check it over a week ago hahaha

Oh well, live and learn through mistakes!

Soon as I swapped the calipers over (The have R and L Stamped on them), to the correct corners, it bled fine and brakes are good.

After driving to and from hampton downs, they work well, but not as well as they should. Solid 6.5/10 though. I'll investigate later.


Bit of a 1 iq day on Friday in the prep for Toyotafest, but it got it going, so I was happy.