jpmountainboy

So I put a new master and slave clutch cyl (and clutch), gravity fed the lines for a hour. I also put fluid in the new master and pumped it through before I installed it.

It was still soft, so I had a buddy pump it with the slave bleeder open and I ran a just about a full large bottle of dot 3 in there before I closed it off. its still soft...Im wondering if maybe I didnt clear the whole system out.

How much fluid have you guys put in when you know youve filled the whole system with new fluid, and what exactly is a bench bleed. I ran a search and saw that a lot but never any instructions, just the gravity bleed.

Thanks for all your help, Im finally about to take my first rebuild out in the snow tomorrow, the clutch shifts fine, it just seems WAY to easy.

happy wheelin

abecedarian

Mine takes about a pint or slightly more to flush completely.
No matter what, it's still got a 'soft' feel to it. That's the difference between hydraulic actuated and cable actuated clutches. Personally, I like the soft clutch- doesn't make my left calf muscle bigger than my right, unlike the Mustang I used to own.

Bench-bleeding is making sure there is no air in the master cylinder- sometimes hard to do when mounted on the vehicle due to the angles that the cylinder is mounted at.

If you depress the pedal and the clutch releases and lets you shift when the pedal is within 1-2" of the floorboard, and doesn't slip when you're on the throttle, you're pretty much fine.

jpmountainboy

so im taking it that you hold the MS with the line hole up so the air can escape when you pump it?

abecedarian

You want air out of the cylinder, so put the 'line hole' as high as possible... higher than the piston if you can....
If it came with the bench-bleed kit: the plastic fitting and some hose... bolt the thing up, attach the plastic fitting and hose, bend the hose over into the reservoir, fill it up with DOT 3/4 fluid and pump the heck out of the pedal as fast as you can until you have no more air bubbles in the m/c when you pump it... and I really do mean pump the pedal as fast as you can.
Then very carefully and deliberately disconnect the fitting (putting your finger over the hole in the m/c to keep any air from getting in there) and connect the line to the slave cylinder. Then as quickly as possible bleed the slave cylinder like you would a brake cylinder, and keep the clutch cylinder full.

abecedarian

And if you've never driven a hydraulic-clutch vehicle, it is quite different than a cable or linkage actuated clutch. If the system's designed correctly, the most heavy-duty / high-pressure plate clutch won't feel much different to disengage than stock... but may feel a bit 'twitchy' or 'sensitive'.

BigBluePile

iTrader: (3)

I think that what I did was filled the clutch MC up and then made sure to cycle the piston thru its full travel. I did this while it was in the truck because I was in a parking lot and I didn't have a bench anywhere. Just make sure that it engages and disengages like it's suppose to and you'll be good.

abecedarian

If you go through the bench-bleed procedure and do your best to keep air out while you change the bench-bleed piping out for the piping to the slave, you can flush the whole system with less than a quart of fluid.

dbcx

A old trick we use is to
Take the top off the slave cylinder
hook a hose the the bleeder and open it
put the ose down in a bottle of fluid and suck it up from the bottom.
That gets air out of something when nothing else ever has.

abecedarian

Your slave cylinder has a 'top'? Mine has a metal body, an inlet from the master, a bleed valve and the piston to the release arm.
At least I think that's what I have. I'll take pictures in the morning- it's 6:30 pm and dark here.

jpmountainboy

Nice!

Thanks for all the input...I love this place!

dbcx

I was thinking the last one i did. It was on a chevy dually.
Still you can take the top off you MC and pump it slowly, it will suck the fluid in from the bottle getting rid of excess air.

abecedarian

You can still end up with a problem where the MC is mounted at an angle where the piston pushes 'up' and the hydraulic line to the slave taps into the MC close to the firewall.... and any air trapped in the MC is above the line to the slave and higher than the fitting to the reservoir.

dbcx

Ok, dont try it then.
I have used this method on many different style trucks and cars, some with no pedal at all. I didnt just make it up to be typing something, just an old school trick. Good luck

abecedarian

that's why I said "...pump the heck out of the pedal as fast as you can..."
one could be creative and put a check valve in the bleeder valve line, close to the bleed valve, and route excess line back into to m/c.



just need someone to close the bleed valve as fast as the person in the cab can pump the pedal.

abecedarian

and was this on a chevy with hydraboost?

dbcx

You dont have to go thru all that. open the bleeder ,pump it it will suck it from the bottle and be done. Sometmes pumping as fast as you can wont do it. Its almost like bleeding your brakes in a bottle. But sometimes when the clutch wont pump up good and get the air out it will suck it back thru and clear the air out. It may not help but I have never had it not help.