Checking Solenoid

WNelms · 31 May 2008, 19:47

Help! I have a 1973 AutoStick that won't go into gear. Using this website as a tool and my Bently Manual I have narrowed it down to I believe a malfunctioning solenoid. I have cleaned and inspected the gear selector contacts. I have checked all of the wiring I have power everywhere all the way back to the solenoid. Inline fuse is good. How can I check the solenoid? Can this be replaced if it is the problem?

Bookwus · 01 June 2008, 00:30

Hiya WN,

Welcome to the group! Always good to have another AutoStick pilot on board.

Insofar as your solenoid goes.................one really has to remove the solenoid from the control valve in order to be sure the solenoid is/isn't working. It's pretty simple really. The solenoid is held in place by four screws. Be sure that you have a screwdriver that fits the slot well because those screws are really in there tight. Take care when backing out the screws as the solenoid will be pushed toward you by the spring which lives inside the control valve. Once you have the solenoid out just hook it up to the hot side of your battery and momentarily touch the negative (ground). If good the plunger should spring out to full extension.

If you should actually need another solenoid.........well, you may have a bit of a problem. Not that they are not available. They are. But in every instance I've seen, they are sold as part of the control valve assembly. I have yet to see a solenoid for sale all on its own. Then again, if you gotta have it................ Used control valves can be found for around $35 to a bit more. Heck, buy the CV and keep it as a spare.

WNelms · 01 June 2008, 06:19

Mike,
Thanks for the info, I had hoped you would be the one to respond as I has always found your post to be the most helpful. Do you have any other thoughts on what my problem might be? The shifting problem had only recently presented itself, every now and then he wouldn't go into gear and I would tap the stick and I could get him into gear. So I though the selector points needed to be cleaned and gapped. So I did that and it worked great for one day and then I haven't been able to get him into gear since. Like I said before I have checked the continuety on everything and I'm good. I do have a nick in the hot wire going to the control valve but would that be enough to cause a drop in the voltage? Once again I really respect your knowledge and experience and any direction would be greatly appreciated.

Bookwus · 01 June 2008, 06:49

Hiya WN,

It's been my experience that when any solenoid goes out, it's gone for good. Self-healers are rare among the solenoids. That being the case, if you had experienced improved (as in back to normal) shifting performance for a bit after gapping the contact points in your shift lever then you would have a solid indication that the problem is not in your solenoid. Just the same, I'd pull it and check it so I could rule it out as the source of your symptoms.

Since the CV solenoid is always "hot", those contact points in the shift lever operate by making a momentary ground for that circuit. If they are unable to make that ground, you won't be able to shift. (Your current situation, right?) Might it be possible that your gap did not hold and the points cannot now make contact? If your continuity is good throughout the circuit (and the car was shifting with a nick in the wire) you are most likely looking at a problem at either end (the shift lever or the solenoid) of the circuit. And since it does not seem to be the solenoid, your shift lever contacts are your best suspects at the moment.

WNelms · 01 June 2008, 22:39

Mike,
I took the solenoid off of the CV left it hooked up to the wires turned the ignition on and had my wife move the gear selector the solenoid works! Now what? On a side note I don't think I have any hose problems because as I unsrewed the solenoid i could hear the air pressure escape. How could my gap be off on the gear selector and it be making the solenoid trigger?

Bookwus · 02 June 2008, 01:39

Hiya WN,

Quote from: WNelms on 01 June 2008, 22:39
.........How could my gap be off on the gear selector and it be making the solenoid trigger?

The simple answer is, it can't.

Which means that the problem you are experiencing lies downstream from the solenoid.

WN, what happens when you try moving the shift lever into gear? Does it actually move into the correct position? Do you get a grinding? More specifics will be helpful at this point.

WNelms · 02 June 2008, 05:33

Mike,
I put everything back together this afternoon, cranked him up and he slipped right into reverse, backed down the driveway into the street and now was unable to get into 1st gear. After I gave the engine a couple of revs I slipped into first. I now realize the method of reving the engine allows me to shift most of the time. Reverse is what really gives the grind. I know I have read posts on here with similar issues. I have one hose that I have not replaced the one that goes from the CV throught the firewall to the torque converter I believe. Right now that seems to be my most obvous culprit. Thoughts?

Bookwus · 02 June 2008, 07:15

Hiya WN,

Bingo!

I'll bet that hose is your culprit. It runs from the control valve through the firewall and forward to the clutch servo. Inside the clutch servo is a rubber bladder/diaphragm. The vacuum sent to the clutch servo by the control valve pulls that diaphragm back which, in turn, pulls the clutch arm. If that vacuum has been compromised (by a leaking hose in this instance although a faulty diaphragm is more common) the diaphragm cannot pull the clutch arm to its full extension. That would most assuredly cause a grinding or a no shift situation. The revving that you're doing is creating more vacuum which allows the shifting.

WN, I'd definitely check that hose (of course, check it for possible leaks but also check to be sure it's not collapsing under vacuum and inspect the connections) and I'd be inclined to check the diaphragm also.

I think you're getting very close.

whyfat2002 · 02 June 2008, 08:50

no no no no no NO. it is not the freaking hose. I just went through this problem my self. what is most likely going on is your control valve's solenoid is starting to go bad. the same thing happened to me. the solenoid on my control valve went bad. I didn't have the time to try and order another control valve so I just bypassed it. I ran some hoses up to my shifter from the vacuum and vacuum tank. added a garden hose sprayer as a "control valve". and wham bam thank you Sam we bypassed the control valve. I recommend you do the same because it actually shifts a lot smoother than the way it was originally. usually the simplistic design works the best. don't believe me here is photographic proof:

my old control valve:

WNelms · 02 June 2008, 23:47

Whyfat,
While I admire your ingenuity, I think that I will stick to trying to figure out how to fix the car with stock components for now.

WNelms · 05 June 2008, 05:41

Mike,
I plan to go to a VW show this weekend in AL so I should be able to find a vendor with the hose I need to replace the last hose from the CV to the torque convertor. Is that one long continuous piece that runs through the firewall to the TC? How long is it?

Bookwus · 05 June 2008, 06:41

Hiya WN,

The hose to which you are referring runs from the control valve to the clutch servo. It is a continuous run. To be honest I don't know offhand exactly how long it is (I'll bet Sean has that figure tucked away somewhere!) but I'd guess that a three foot length would cover the run. Look for 12 mm braided hose and buy a few inches more than three feet just for insurance.

68autobug · 05 June 2008, 07:16

I had a similar problem
My car started crunching the gears...
and it got worse and worse
until reverse was just about impossible
as i had to rev the engine and reverse is so low a ratio

it turned out I had forgotten to tighten a hose clamp on the hose going to the vacuum tank

which meant when I revved the engine, I had enough vacuum
but at idle too much vacuum was leaking from the hose...

so all the hoses and the clamps need to be correct..

and although its no1 for ingenuinty
with a hose squirter on the gear shifter
I'm sure no one would try to steal the car... lol...

I wouldn't really try to drive without a control valve..

You can test the control valve by turning the ignition on
and short out the ground wire with another piece of wire..
it should click..
or just have someone move the gearshifter while you
check it and hold your hand on the control valve to feel it click

cheers

LEE

68autobug · 05 June 2008, 08:48

that hose N0203901 12mm x 590mm long.. {I think??]
other hoses being 430mm and 550mm long..

cheers

LEE

WNelms · 05 June 2008, 19:11

Thanks for the info guys, I will let you know how the weekend project pans out.