Observations and impressions for bleeding the 1500 clutch system

[RichBall]

There have been a few threads posted here recently on problems bleeding the 1500 Midget’s Hydraulic clutch system. Since I just recently had similar issues I thought I would post my observations, impressions and solutions.

A few weeks ago I went out to take the Midget for a spin up to the store and was greeted by a non functioning clutch pedal. After investigating a bit I came to the conclusion that the slave cylinder had finally given out on me. I ordered an original Lockheed rebuild kit from Peter C., did a light honing pass to clean it up and rebuilt it. After getting everything back in and buttoned up I called for my lovely assistant Susan (wife) and we set about trying to bleed it. Trying is the key here. We spent an hour plus and at least a pint of LMA trying to get it working with no luck.

I see two areas in the system that contribute to problems bleeding in the traditional way.

The first problem I needed to over come was the air that was trapped in the arch of the line connecting the master to the slave. On the 1500 the line is a transparent tube that arches up before heading down to the slave. The problem I was having was that the volume of fluid being sent through the line was not sufficient to move the air down the vertical rise. The air bubble would slide up past the fluid and back to the high point of the arch. Phil Jones came to my aid here by loaning me his Eezibleed system. This pressurized bleeder worked great and was able to move enough fluid under pressure to move the air bubble out of the line. Unfortunately it took up residence in the slave cylinder.

The second problem I came across has to do with the bleed valve on the slave. First off it is located slightly below the high point of the cylinder so any trapped air can not flow out easily even with the rear of the car raised above the front. Adding to this is the limited space to rotate a wrench placed on the bleed valve. You’re only able to open the bleed valve a slight amount to release the fluid with a flair nut wrench and hose on the bleed valve. This low flow was not enough to force the air out of the slave. What I found worked well was to use a 7/16 box wrench that could slide off over a hose on the bleed valve so I could reposition the wrench and rotated it again several times. This allowed me to open the valve much wider. This in combination with the pressure of the Eezibleed to move the fluid cleared all the air that was still trapped in the slave.

From my experience the most successful way to bleed the clutch on the 1500 Midget is to have a high fluid flow rate so the air in the system gets caught up with the fluid flow and pulled out along with it.

Sorry if this was long winded, but I thought it might be useful to others that are having the same problem.

Rich Ball
’76 Midget

 

[Boink]

Nice summary. I struggled with my 1275 (in a Bugeye)... getting it close but not quite close enough without a lot of struggle. There sure are a lot of recommended ways of doing this, including:
a) the old-fashioned way of repeated peddle action with intermittent opening of the bleeder (which is awkward)
b) the pressure through the master reservoir method (some using rubber bicycle inner-tube with air pressure)
c) the syringe method to pump fluid up the system from the bleeder.
I would have loved to pump a high volume of fluid through the system, but it's not often practical.
It shouldn't be this hard, but if often is (and certainly longer than replacing the slave itself).

 

[aeronca65t]

I generally bleed the 1500 setup by:

1. pump the clutch several times and hold down.
2. Loosen the line going into the clutch master cylinder, let air spurt out and re-tighten.

This is messy (put a lot of rags under the line that you are loosening). But it really seems to work well.
I tend to do this on my 1275 car too.

 

[JPSmit]

And, FWIW, I take the MC off the car, hold it higher than the turn of the line, pump a few times and reinstall, takes minutes

 

[bthompson]

Also a method that works: remove the slave cylinder, hold it high, and let the bubble drift up the line into the slave. Then you can (still holding the slave) pump the pedal and crack the bleeder. (Make sure you're not holding the slave facing the body.)

Bleeding the clutch in place on the 1500 is a one-man job if you have a ratchet with several extensions and a wobble-joint. Thread the extensions through the tranny tunnel access hole and you have nearly a straight shot to the bleeder. You can crack the bleeder from the driver's seat -- with a little dexterity you can time a swift pump-and-crack routine to push that bubble right down to the slave before it drifts back up.

 

[PSJ]

Thanks for the "shout out", Rich! Glad it worked out.

If you could snugly pack the Eezi-bleed for it's return in a nest of $100 bills, I'd appreciate it! :friendly_wink: