Hydraulic boo boo? Little help?!

[Stomis]

So I got my truck all buttoned up and I think I made a mistake here. I put an internal throwout NV3500 in it using the stock 3/4in clutch master. The master from the application the trans comes from is also 3/4. The only thing I changed hydraulically is that I went from the quick disconnect line to a -4 AN line. The -4 line is 1/4 and Im fairly certain the factory line is 3/16ths.

Well the problem Im having is the slave cylinder does not want to fully disengage the clutch when the clutch pedal is maxed at the bottom. Will the change in hose size in turn reduce the travel the master puts on the slave cylinder?

Ive never really played with mix match hydraulic stuff. I had just thought the line would hold extra volume but the displacement was the displacement...

Help?

 

[jt512]

The difference in hose size should not matter. Think of it like this, when the system is full and you push the pedal and move X amount of fluid through the hose to the slave cylinder the diameter of the hose should not affect the volume of fluid moved by your master cylinder.

 

[Stomis]

The difference in hose size should not matter. Think of it like this, when the system is full and you push the pedal and move X amount of fluid through the hose to the slave cylinder the diameter of the hose should not affect the volume of fluid moved by your master cylinder.

I didnt think so the more I sat and thought about it. My friend suspected it since it was the only thing I changed. I come to research the slave is made to work with a 3/4 master. Thats the factory setup. I bought a mityvac. Guess I'll find out if theres a stubborn air pocket in the master diminishing travel at the other end...

 

[DEMON44]

Yep no hydraulic change in hose size IF is already full of oil.

The only way to change ratio is change master or slave.

 

[diesel4me]

There is no adjustment at the pedal push rod,is there?...some trucks had a threaded coupling that can be lengthened or shortened ..if not,then its still airbound some probably..

 

[Stomis]

There is no adjustment at the pedal push rod,is there?...some trucks had a threaded coupling that can be lengthened or shortened ..if not,then its still airbound some probably..

Internal throwout style slave, so no. Only way to adjust it is to pull the trans and make a spacer plate between it and the trans but it cant possibly be that because the trans uses the same exact throwout bearing as a t56 which works on small blocks no problem.

Gotta have air in it...

 

[DEMON44]

Yep.

 

[FOR MUD]

Sometimes they are a bugger to bleed. It took me an hour and half one time. The harder it is to the slave.....The harder it is.

 

[diesel4me]

My friend had a hard time bleeding his S-10's clutch when he replaced everything-master,slave (which was the throwout bearing) ,and the disc,pressure plate and the pilot bushing..

I helped him pump the pedal while he bled it a good 20 minutes..he was disgusted..I suggested we try using vacuum,and we pulled a hose off the engine that had manifold vacuum at idle and he shoved it on the bleeder screw with the engine running..a few seconds later the engine started missing and white smoke came out of the tailpipe--which meant brake fluid was sucked into the intake.....I shut it off,he closed the bleeder and I tried the clutch,it was fully bled!..I have used that trick on brakes when I'm alone and had no one to help me ...

His engine smoked for a few minutes and idled rough until the brake fluid burned off..no harm done..you can rig up a glass jar with two nipples soldered to the lid so the brake fluid wont get sucked into the engine if you wish..

 

[Stomis]

I just vacuum bled it from the top with a mighty vac for 20mins. Lots of tiny air bubbles but no change in clutch behavior. Guess I'll try the mighty vac from the bottom but I was under the impression bleeding from the master reservoir with the vacuum pump would bleed the entire system.

I'm wondering how bad of an idea it would be to lengthen the rod into the master...

 

[sweetk30]

did you give it fluid at the bottom to suck up with the air ?

if not you didn't do much at all.

 

[Stomis]

did you give it fluid at the bottom to suck up with the air ?

if not you didn't do much at all.

No I didnt the air bubbles came up, trapped in the line and when I removed the hose the fluid in the reservoir sucked down to displace the vacuum no? Every guide Ive read said nothing about feeding it fluid through the lower bleeder but its worth a shot.

 

[Stomis]

Welp Im jumping up to a 7/8s master. Its a common upgrade for t56 cars (aka same hydraulics) so its kinda getting another upgrade done at the same time. I talked to my local speed shop guy today who recommended and ordered me the clutch. His advise was to step up the master. He said this is why he said if I wanted a clutch that wasnt listed as compatible with the nv3500/4.3 that he couldnt guarantee the hydraulics would work. I made that decision to go with a standard SBC clutch after talking to Russell about it. He had told me he had no issue with the hydro throwout bearing with a square body master. Both me and my parts guy think the throw issue is stemming from the hayes clutch being so heavy that the clutch finger fulcrum requires more throw to disengage the clutch in order to ease the pedal for a traditional clutch.

So I went to the store and picked up a 95 F350 Powerjoke master. Its 7/8 bore, has a removable mounting plate so I can fab the correct one for my firewall and takes the same type of roll pin fitting. Im dreading making a new line for the throwout since this master is front discharge but it is what it is. Even if I cheated some more throw out of my stock master my clutch would be coming on right off the floor. Im going to make this rod adjustable and be careful with setting a new stop to not over extend the slave cylinder.

Hopefully all will be well and the trans isnt coming out...