Turbo brake issues
#1
Drifting
Thread Starter
Turbo brake issues
I replaced the rubber brake lines with stainless, and one from the firewall to the front pax side frame mount. All new pads, rotors, and checked the booster for input vacuum (10 psi) and checked that the booster holds 10 psi vacuum. I bled all the lines in the proper order and yet, I still have to stand on the brakes and they are very ineffective. They don't feel boosted and it takes about 1 1/2 inch play before engaging. What could I be missing?
#2
Rennlist Member
[QUOTE=mytrplseven;15544078]I replaced the rubber brake lines with stainless, and one from the firewall to the front pax side frame mount. All new pads, rotors, and checked the booster for input vacuum (10 psi) and checked that the booster holds 10 psi vacuum. I bled all the lines in the proper order and yet, I still have to stand on the brakes and they are very ineffective. They don't feel boosted and it takes about 1 1/2 inch play before engaging. What could I be missing?[/QUOTE
What procedure was used to bleed the brakes. The "play" indicates to me there is air in the brake system.
What procedure was used to bleed the brakes. The "play" indicates to me there is air in the brake system.
#3
Rennlist Member
I recently replaced my lines with stainless while doing a clutch job on the car as well. I did have to make several circuits around the car bleeding the calipers as well as bleeding the clutch slave cylinder. Getting all of the air out of it was challenging and repetitive work. At the time it was still possible to buy blue fluid to swap with amber to make sure I got a complete exchange of fluid on each try. I also used a hard plastic mallet to knock the calipers while bleeding them.
To get the last of the air out I bled the clutch slave cylinder from below, using a squeeze bottle to force fluid from the bleed nipple to the reserve tank. I also raised the rear of the car, bled all the calipers, then raised the front and bled them again.
To get the last of the air out I bled the clutch slave cylinder from below, using a squeeze bottle to force fluid from the bleed nipple to the reserve tank. I also raised the rear of the car, bled all the calipers, then raised the front and bled them again.
#4
Drifting
Thread Starter
[QUOTE=T&T Racing;15544156]
Motive Flow pressure bleeder.
I replaced the rubber brake lines with stainless, and one from the firewall to the front pax side frame mount. All new pads, rotors, and checked the booster for input vacuum (10 psi) and checked that the booster holds 10 psi vacuum. I bled all the lines in the proper order and yet, I still have to stand on the brakes and they are very ineffective. They don't feel boosted and it takes about 1 1/2 inch play before engaging. What could I be missing?[/QUOTE
What procedure was used to bleed the brakes. The "play" indicates to me there is air in the brake system.
What procedure was used to bleed the brakes. The "play" indicates to me there is air in the brake system.
#5
Drifting
Thread Starter
I recently replaced my lines with stainless while doing a clutch job on the car as well. I did have to make several circuits around the car bleeding the calipers as well as bleeding the clutch slave cylinder. Getting all of the air out of it was challenging and repetitive work. At the time it was still possible to buy blue fluid to swap with amber to make sure I got a complete exchange of fluid on each try. I also used a hard plastic mallet to knock the calipers while bleeding them.
To get the last of the air out I bled the clutch slave cylinder from below, using a squeeze bottle to force fluid from the bleed nipple to the reserve tank. I also raised the rear of the car, bled all the calipers, then raised the front and bled them again.
To get the last of the air out I bled the clutch slave cylinder from below, using a squeeze bottle to force fluid from the bleed nipple to the reserve tank. I also raised the rear of the car, bled all the calipers, then raised the front and bled them again.
#6
Rennlist Member
Maybe the issue is Brake MC.
#7
Drifting
Thread Starter
Looks like it's back up on the jack stands....again. I'll pull all the wheels, check the pads for possible glazing, and then kick myself for not replacing the master cylinder while I had it and the booster off. I may have to buy dot 4 by the case at this rate.
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#8
Rennlist Member
If I was in your situation, try brake bleeding one more time before replacing MC. The Motive pressure should be about 10 psig and ensure the brake fluid is covering the pickup tube at all times. I place the Motive tank so it is on an incline with the pickup tube on the downward slope so all the brake fluid is at the end of the pickup tube
#9
Drifting
Thread Starter
If I was in your situation, try brake bleeding one more time before replacing MC. The Motive pressure should be about 10 psig and ensure the brake fluid is covering the pickup tube at all times. I place the Motive tank so it is on an incline with the pickup tube on the downward slope so all the brake fluid is at the end of the pickup tube
#10
Rennlist Member
Buy the cheap DOT 4 stuff to bleed the system. In practice, I just recover the stuff I've already used with a catch bottle, it reduces cost significantly. Once you have good brakes, clean the Motive and fill it with the good stuff. Go through one more complete cycle of bleeding the calipers and clutch with the high grade/high temp fluid you plan on using and discard the cruft you've used to bleed.
When you could buy two different colors of ATE, it was easy. Now you need to do it by volume since there's no obvious color change in the fluid.
#11
Drifting
Thread Starter
This is a pet peeve of mine; one I fret over ever since the "Bureau of Automotive Fluid Colors" took over in the US.
Buy the cheap DOT 4 stuff to bleed the system. In practice, I just recover the stuff I've already used with a catch bottle, it reduces cost significantly. Once you have good brakes, clean the Motive and fill it with the good stuff. Go through one more complete cycle of bleeding the calipers and clutch with the high grade/high temp fluid you plan on using and discard the cruft you've used to bleed.
When you could buy two different colors of ATE, it was easy. Now you need to do it by volume since there's no obvious color change in the fluid.
Buy the cheap DOT 4 stuff to bleed the system. In practice, I just recover the stuff I've already used with a catch bottle, it reduces cost significantly. Once you have good brakes, clean the Motive and fill it with the good stuff. Go through one more complete cycle of bleeding the calipers and clutch with the high grade/high temp fluid you plan on using and discard the cruft you've used to bleed.
When you could buy two different colors of ATE, it was easy. Now you need to do it by volume since there's no obvious color change in the fluid.
#12
Rennlist Member
I've been buying ATE 200 and plan to do occasional Xcross. Do you think normal Dot 4 would be ok or should I stick with the higher temp stuff? My plan is to try a few more bleeds and pull the pads to check (since I'm in there anyway) to see if there's any glazing of the pads. Replacing the MC would be my last resort if nothing is resolved by then.
#13
Three Wheelin'
I Sort of had the same problem with My Turbo-S … I used to have to STAND on the pedal, and that is not a comfortable feeling at Watkins Glen, and It really will mess with any heel-toe Downshifting.. Anyhow, I ended up getting a Caliper rebuild Kit, I did all 4 calipers.... 16 pistons.. Took my time and was very detailed in the cleaning all new o-rings, got 30 years of junk and varnish out of the calipers. Put it all back together... Took it for a rip on the street and was a TOTALLY different car at the track.. It was amazing the difference the rebuild made... they work awesome now.
Look on YouTube, Van has a great Video on how to rebuild/clean them...I got my rebuild kit from Racers Edge. I took my time and it was about an 8 hour job. FYI You Don't need the scraper rings.. just the seals..
Look on YouTube, Van has a great Video on how to rebuild/clean them...I got my rebuild kit from Racers Edge. I took my time and it was about an 8 hour job. FYI You Don't need the scraper rings.. just the seals..
#14
Three Wheelin'
This is a pet peeve of mine; one I fret over ever since the "Bureau of Automotive Fluid Colors" took over in the US.
Buy the cheap DOT 4 stuff to bleed the system. In practice, I just recover the stuff I've already used with a catch bottle, it reduces cost significantly. Once you have good brakes, clean the Motive and fill it with the good stuff. Go through one more complete cycle of bleeding the calipers and clutch with the high grade/high temp fluid you plan on using and discard the cruft you've used to bleed.
When you could buy two different colors of ATE, it was easy. Now you need to do it by volume since there's no obvious color change in the fluid.
Buy the cheap DOT 4 stuff to bleed the system. In practice, I just recover the stuff I've already used with a catch bottle, it reduces cost significantly. Once you have good brakes, clean the Motive and fill it with the good stuff. Go through one more complete cycle of bleeding the calipers and clutch with the high grade/high temp fluid you plan on using and discard the cruft you've used to bleed.
When you could buy two different colors of ATE, it was easy. Now you need to do it by volume since there's no obvious color change in the fluid.
1. open bleeder
2. pick up beer and drink
3. Put beer down when color changes close bleeder
4 Repeat 7 more times
#15
Rennlist Member
Don't forget to bleed the clutch.