Clutch Bleed Idea
05-20-2015, 08:37 AM
#1
Clutch Bleed Idea
Ok so I found out something on my motorcycle clutch that may have promise for cars.
I picked up a '84 Honda Nighthawk with a hydraulic clutch and it was shifting a bit notchy with some drag between shifts. I suspected clutch drag and wanted to replace the fluid to get a better "push" on the slave cylinder rod. I read on a bike forum suggesting that a block of wood be placed on the handlebar grip to prevent the clutch lever from touching the handlebar when bleeding using the "pump the master" method. I tried this out this morning and it was the fastest bleed I ever did on a clutch and it worked great. I used a paint brush handle as my block of wood and the clutch lever stops at that point. So I suspect between the fresh fluid and the block method, I'm getting a much better throw on the clutch with nothing left on the table.
That being said, this bike's system looks to be the same the same as my ZF equipped C4. So I'll try a similar method with the car, but it's a 2 man job so it's going to be a while before I can try it. In the meantime if someone has notchy or hard shifting, it's worth a shot. I'm not sure how much to limit the clutch pedal travel for the experiment, but perhaps 1/8". Please try this at your own risk.
http://katriders.com/vb/showthread.php?t=92873
I picked up a '84 Honda Nighthawk with a hydraulic clutch and it was shifting a bit notchy with some drag between shifts. I suspected clutch drag and wanted to replace the fluid to get a better "push" on the slave cylinder rod. I read on a bike forum suggesting that a block of wood be placed on the handlebar grip to prevent the clutch lever from touching the handlebar when bleeding using the "pump the master" method. I tried this out this morning and it was the fastest bleed I ever did on a clutch and it worked great. I used a paint brush handle as my block of wood and the clutch lever stops at that point. So I suspect between the fresh fluid and the block method, I'm getting a much better throw on the clutch with nothing left on the table.
That being said, this bike's system looks to be the same the same as my ZF equipped C4. So I'll try a similar method with the car, but it's a 2 man job so it's going to be a while before I can try it. In the meantime if someone has notchy or hard shifting, it's worth a shot. I'm not sure how much to limit the clutch pedal travel for the experiment, but perhaps 1/8". Please try this at your own risk.
http://katriders.com/vb/showthread.php?t=92873
05-20-2015, 09:28 AM
#2
I got a cheap vacumm pump from harbor frieght works great and one man job
05-21-2015, 08:11 AM
#3
I started yesterday on the motorcycle clutch using the Mityvac and got less than stellar results this time as well as in the past so I changed to the pump the lever method. I think the Mityvac tends to suck air into the threads and the clutch is more sensitive to this then the brakes. I think it works great on the brakes though, but I always finish the brakes by pumping them. With the synchro rebuilds on a ZF being so expensive, I'm not going to take any chances.
In addition, some of the slave nipples are on the bottom and difficult to get all the air out. I'm going to try the fluid push method instead of the vac. I picked up a cheap one from this guy on ebay since the Mityvac hydraulic fluid injector is discontinued:
http://www.ebay.com/usr/2014_amb_sal...p2047675.l2559
In addition, some of the slave nipples are on the bottom and difficult to get all the air out. I'm going to try the fluid push method instead of the vac. I picked up a cheap one from this guy on ebay since the Mityvac hydraulic fluid injector is discontinued:
http://www.ebay.com/usr/2014_amb_sal...p2047675.l2559
05-21-2015, 05:40 PM
#4
I use a vacuum pump for a/c systems with the cup from a mityvac kit. Leave the MC cap off and when the bleed is good it will pour out of the bleeder screw by gravity. Then just tighten it.