Spitfire Clutch question for Spit drivers...

[IanF]

Where does your clutch grab in the travel?

After driving Baldrick a few times now and after repeated bleedings of the new M/C and S/C, it just seems like there is no "give" whatsoever between disengaged at the floor and engaged about 1/2" off the floor. I don't remember it being that low...

We had the flywheel surfaced while everything was apart, but the clutch disc and pressure plate looked good, so we just put them back in... I'm really hoping that wasn't a mistake... /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

 

[Andrew Mace]

Ian, it shouldn't be that low a point of engagement / disengagement! More than likely, there's still a bit of air in the line; I can't see why reinstalling the pressure plate and disc should cause any problems.

 

[Jerseygirl]

Is there some strange "trick" to bleeding one of these clutches that we don't know about? Ian has bled this thing at least three times now and it still doesn't behave anywhere near like it used to. /bcforum/images/%%GRAEMLIN_URL%%/frown.gif

 

[TR3driver]

I'll offer two things that may or may not help (never tried on a Spit) :

1) I've had really good luck with just making sure there is plenty of fluid in the reservoir, then pumping the clutch up as high as I can get it, holding it to the floor for 15-20 seconds, and releasing it. If necessary, repeat the process a few times.

2) Try dismounting the slave and holding it so the bleed valve is uppermost. Crack the valve, and wait for the fluid to flow out by itself. Any bubbles will come out first.

 

[AltaKnight]

I always bleed the clutch (or brakes) with an assistant (usualy my 20 year old daughter or her boyfriend or my wife as a last resort) in the driver seat and me under the car.
The following is the process I use and it always seems to work.
I put the free end of the bleed hose into a half filled jar of brake fluid and make sure the end stays submerged at all times.
1) Loosen the bleed nipple
2) Have the assistant push in the clutch and hold it at the floor
3) Tighten the bleed nipple again
4) Let up the pedal
5) Repeat the process again & again (about 10 times)
6) Check/refill the master every 2nd press of pedal
Good communication between clutch pusher and bleed nipple operator is the key here.

 

[jdubois]

Good communication between clutch pusher and bleed nipple operator is the key here.

Because of that, and having a hard time recruiting people who care enough to do it right, I tried the nipples with check valves in them from https://www.speedbleeder.com and they work so well I now order a new set for any car I buy.

 

[IanF]

Bleeding a Spitfire clutch is a one-person job as the slave can only really be accessed from the passenger compartment with the tunnel removed.

I'll try removing the slave from the bell housing and bleeding it again.

 

[Guest]

I feel like for some reason that I have read in two or three different places that you needed to bench bleed a new clutch master cylinder first on Spitfires. I can't tell you where I have read this but it has been stuck somewhere in the back of my mind. I just got my clutch master repair kit in the mail today. It's not leaking, but with all the other seals on the car being dried out I was going to do it anyway. Maybe I'll just wait until a problem developes.

Mine grabs at about 1/2 pedal. It feels good to me at that point.

 

[Andrew Mace]

One bleeding trick that SOMETIMES works for me is as follows. Start by bleeding normally. When it all seems to be going well, do 2-3 short, quick strokes of the pedal using ONLY THE BOTTOM HALF of the travel, then hold the pedal down and close the bleed screw. Don't remember where I first learned about it, but it's worked for me on clutches.

And yeah, with the gearbox cover off, it IS a one-person job: palm of one hand working the pedal and other hand opening and closing the bleeder! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[RonMacPherson]

Another option is to pressure bleed from the slave through the master cylinder.

If you have a mity-vac, or some other vacuum pump type tool, you can apply the hoses to the outlet port(usually the capped one on top of the pump by the gauge) fill the reservoir of the mity vac with clean fluid, apply the hose to the bleed valve on the slave cylinder(then with the master cylinder low on fluid) pump until you see fluid emerging into the reservoir. Clutch master cylinders do not have one way check valves so this is a very easy, one man bleed system that I've used for over 20 years.

One thing I would check also, before bleeding, is to make sure that you have the spring behind the valve in the slave cylinder and that it is pushing the valve(piston cup) out to the end of its travel.

 

[jdubois]

It's not leaking, but with all the other seals on the car being dried out I was going to do it anyway. Maybe I'll just wait until a problem developes.

Well, with my fuel pump disaster still fresh in my mind, I'd say definitely wait until there's a problem!

 

[IanF]

Yeah, I did bench-bleed the MC before hooking it up to the slave. I've read that about all MC's for years, regardless of the car...

I'll try Andy's 3-pump method.

Ron... not sure what you mean... the slave was new... but the relative piston position looked the same as the old one...

I'm drawing a blank: is the flywheel a single plane or stepped surface like in some trucks? /bcforum/images/%%GRAEMLIN_URL%%/blush.gif

 

[Guest]

The slave locks into the collar correct?

 

[IanF]

The slave locks into the collar correct?

Yes. Not sure the clutch would work at all if it didn't... /bcforum/images/%%GRAEMLIN_URL%%/hammer.gif