[DeTomaso] CNC Clutch, problems bleeding

Tomas Gunnarsson guson at home.se
Tue Jul 28 05:11:09 EDT 2009


Asa Jay,

You have two issues it seems. The master spring can not be relied on to return the pedal. There's a return spring on the pedal, it's there for a reason. With the master cylinder out, the pedal must be able to return to the stop on its own. In your case it's obvoius that you have some kind of pedal travel issue as you have to pull the pedal against the stop to fill the master from the reservoir. You also mention pulling the slave out until it almost makes contact with the throwout bearing. This is a similar problem, you should be at that point at rest with the slave. You have a slave cylinder adjustment issue.

Tomas

----- Original Message ----- 
From: "Asa Jay Laughton" <asajay at asajay.com>
Cc: "Tomas Gunnarsson" <guson at home.se>
Sent: Tuesday, July 28, 2009 5:01 AM
Subject: Re: [DeTomaso] CNC Clutch, problems bleeding


> Bench bleed it, did that already.
> Push it down to make sure the ports are lined up.  Huh?  If anything, 
> the rubber cup is covering the ports from the pedal already being 
> depressed.  Anyway, it seems to be a combination of problems, I think.
> 
> I picked up a vacuum pump brake bleeder kit from Napa.  Hooked it all up 
> and got NOWHERE.  Nothing was moving, fluid level the same, and I -know- 
> the lines were clear as I blew it all out with compressed air.
> 
> So I reach under the dash and pull the pedal about a quarter inch toward 
> the back of the car.  Shlluuuuurk, out went the fluid.  Refill the 
> reservoir, pump the vacuum again, repeat.  Eventually I got the entire 
> line filled.  Now, it -may- still have some air in it, I'm not sure.  
> But here is the thing.
> 
> At rest, the slave likes to come a long way back.
> At rest, the pedal isn't quite all the way up.
> When pressing in the pedal, I don't get the kind of resistance I expect, 
> and not enough pedal travel to release the clutch.
> 
> If I pull the pedal all the way up, then go to the slave and pull it out 
> so it's just ready to contact the throw-out bearing, I can depress the 
> clutch and get some good release action, and see the clearance open up 
> at the disc.  So what gives?
> 
> The master only springs back from spring pressure inside the master.  
> Out of the car, it comes all the way back against the snap ring just 
> fine.  In the car?  I'm not so sure.  The slave has this massive spring 
> that pulls back the lever, but even the adjusting screw is all the way 
> in and still doesn't touch the stop.  There is about a half inch in 
> between the stop and the adjusting screw, so I can't get it to "rest" 
> farther out because there is nothing to stop it, (at least not yet).
> 
> Photos would probably be good, but I've not taken any yet.  I'm at that 
> "need the experience of others" point.
> 
> Thanks,
> Asa Jay
> 
> Asa Jay Laughton, MSgt, USAFR, Retired
> 
> & Shelley Marie
> Spokane, WA
> 
> 1971 Mach I Mustang  [ASA JAY]
> 1973 Pantera L 5533  [ASASCAT]
>    
> ******************************     
> http://www.asajay.com
> http://www.teampanteraracing.com
>  
> 
>



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