Topic: Tilt Away Column Question

[eric lipper]

I am sorting out the last few details on a GT500 convertible and the tilt away has me a little baffled.  When I turn the car off and open the door the column tilts away correctly.  The problem is that I can't get it to relatch and the ignition interrupt prevents a restart.  If I unplug the vacuum line at the vacuum switch I hear the air escape (i.e. good strong vacuum) and then the piston in the vacuum motor will return, the cable will release, the wheel will latch and the car will then start.  So what releases the vacuum?  I have the book that you can purchase but it does not seem to describe what makes the vacuum motor return to its position when it allows the car to start.

[67gtasanjose]

Check the solenoid vacuum valve to see if it is adjusted correctly and that it opens and closes off the vacuum supply correctly.

[RoyceP]

Sounds like the cable is a bit too loose or tight. It's a critical adjustment. Of course it won't latch with the door open.

Another thing, check the column to make sure the latch assembly is not worn or in need of lubrication. That can make them act like you describe too.

[Bob Gaines]

Sounds like the cable is a bit too loose or tight. It's a critical adjustment. Of course it won't latch with the door open.

Another thing, check the column to make sure the latch assembly is not worn or in need of lubrication. That can make them act like you describe too.

Eric,you are trying to trying to re latch with the door closed right?

[eric lipper]

Bob, yes.  I have done it with the door closed and also by depressing the door light switch and tilt away switch simultaneous to simulate the door closed just in case the door was not fully closing the switch. 

The tilt away feature seems to work fine on unlatching.  From my view when Jim Cowles did the restoration he appears to have used NOS parts because the vacuum motor and solenoid switch look (cosmetically) really nice.  The off-white color of the plastic on the vacuum motor even looks new as does the plating on the bracket.  Even the cable looks good.  The only observation that I have made is that the adjustment on the cable has clearly been tried a few times before because you can see the scratches that the single screw made in the adjustment bracket slot when it has been moved. 

If I understand the system correctly (I am a novice) it seems to me like the solenoid switch gets power and activates by receiving 12 volts when the door is opened.  When the solenoid receives 12 volts that opens the valve that allows residual vacuum from the can under the battery to go into the vacuum motor.  If all goes well then the vacuum motor piston retracts pulling the cable and viola the pawl is unlatched.  The car will not then start because the vacuum motor interrupts the wire between the starter switch and the starter solenoid.

I have that book that you see on the web that helps diagnose the system but there really is not much explanation of what happens in reverse which, of course, is my problem.  Here is my guess and let me know where I am wrong because these are all guesses:

1. When the door is closed that removes power from the solenoid so the solenoid returns to closed?  If yes, I guess a test light would confirm that the power is removed?
2. I am envisioning that when the solenoid closes it bleeds off the vacuum in the vacuum motor thereby allowing the piston to fully extend?
3. Once the piston fully extends that restores the full function of the ignition solenoid and also releases tension on the cable so the pawl will catch?
4. If the pawl catches then the column locks and the car starts?

Here are my diagnostic guesses:

1. The cable/pawl arrangement seems sound because it unlatches fine and if I remove the vacuum hose from the solenoid it relatches fine and the car will start.
2. I guess the tiltaway door switch must be good because the column will successfully unlatch.
3. I am assuming that wherever (or however) it unloads the vacuum (if that is how it works) that function is not working.

All advice on this one is appreciated.  It is the only item on the car that does not function correctly so my focus on it is intense.  It did not work right when I bought the car so I removed its vacuum source and removed the power wire from the solenoid so that I did not get the situation where the column will not latch and the car not start.

[Bob Gaines]

Sorry I hesitate to get involved with a diagnosis by remote. The only thing I will say is that the plastic on the vac canister is typically black on 69 and white/creme on 68 and earlier. There is also a 68 tilt bracket and a 69 tilt bracket . I am wondering if the correct one was installed given the vacuum canister. I am not sure what the consequences if any there are if a 68 bracket was installed in a 69.The shape of the bracket may have to do with the orientation of a component or maybe not.  I usually have to see things and study them then walk away do something else then come back before I find the solution.I hope someone chimes in that has your answer. You can go on Pete's website and see a picture of the bracket shape for 68.

[67gta289]

If I unplug the vacuum line at the vacuum switch I hear the air escape (i.e. good strong vacuum) and then the piston in the vacuum motor will return, the cable will release, the wheel will latch and the car will then start.  So what releases the vacuum?

Can you clarify the statement above?  There is no "vacuum switch".  The two vacuum related components in the passenger compartment are (1) the vacuum release valve (aka solenoid valve) and (2) the vacuum release motor.  Did you unplug the source hose into the vacuum release valve - item (1), or either end of the short hose between items (1) and (2)?

If you enter the vehicle, close the door, and pull the steering wheel to normal position the aforementioned item (1) vacuum release valve will be de-energized, and bleed vacuum off of the connection to the item (2) vacuum release motor, and the wheel should remain in place.  If you followed these steps and the wheel did not latch, the first thing to do is to check the vacuum system, which is what Richard was alluding to in the first reply.

Go ahead and re-establish the conditions you originally had - a fully charged vacuum canister, engine recently shut off, door open, wheel away.  Check the voltage on the wire feeding the item (1) vacuum release valve.  It should be 12 volts, because this is what energizes the vacuum release valve which ports vacuum to the vacuum release motor.   Step 1 will be to make sure that the electrical system is working properly.  When a voltmeter still on that circuit, close the door.  This should result in the door jamb switch being engaged, opening the contact to the interposing relay coil, and interposing relay contacts opening, de-energizing the vacuum release valve.   If that is not the case, we need to drill down further into this electrical circuit.  Please advise.

If the electrical circuit works as described, then I go back to your statement describing "good vacuum" "escape" followed by being able to latch.  I would suspect that the item 1 vacuum release valve, which is essentially a solenoid valve, is malfunctioning.  Not enough leakage, mind you, to release the latch under normal conditions; but enough leak-by that prevents proper bleeding and subsequent latching.  The actual bleeding is done at the item 2 vacuum release motor.  In other words, I don't think that the solenoid is a three way valve design...but I have not taken one apart to be certain.

Based on what you described, I don't think there is any problem downstream from here, such as with linkage, cables, etc.  After all, when you released vacuum from the vacuum release motor everything worked as expected, which tells me that all of the mechanical wizardry is fine.

[RoyceP]

It sounds like the cable is just barely too tight. It needs to be as tight as it can be without releasing the column.

[eric lipper]

I spent about an hour tonight looking at it and after putting a little lubrication on the vacuum motor (the thing that pulls the cable) I could get it to work better but still not reliably.  Basically if you wait a minute or two it eventually slides into position.  I think the problem is that it is just not sliding in the cylinder as well as it should.  I think I am going to give up for now and just keep it bypassed.  Attached is a picture of the unit in my car.

[eric lipper]

I have now concluded that the cable is too stiff.  It could be that the grease on the pawl is dry or the cable has a problem.  When I manually pull on the cable it does not seem to lock back very well so I guess the reason pulling vacuum helped was because it helped the cable to slide back.  My unit is white instead of black but it has the interlock built in so who knows.

[krelboyne]

The vacuum needs to bleed off from the vacuum valve, soon after use. If it continues holding vacuum, the cable will not be allowed to release.
I remember our (now retired) tilt guy saying this.

[Bob Gaines]

I spent about an hour tonight looking at it and after putting a little lubrication on the vacuum motor (the thing that pulls the cable) I could get it to work better but still not reliably.  Basically if you wait a minute or two it eventually slides into position.  I think the problem is that it is just not sliding in the cylinder as well as it should.  I think I am going to give up for now and just keep it bypassed.  Attached is a picture of the unit in my car.

I am not sure why the pictures of the engine compartment and a wide shot of the front of the car are included in reply #8 other then to showcase a beautiful car because they are unrelated to the tilt away issue. Not appropriate to comment on this thread given the subject matter but as you are apparently after historical correct presentation you may want to start a new thread with that in mind and ask about what is not historically correct under the hood and on the exterior in those pictures for fine tuning the historical look.That is if you are curious. If not disregard.

[Bob Gaines]

I have now concluded that the cable is too stiff.  It could be that the grease on the pawl is dry or the cable has a problem.  When I manually pull on the cable it does not seem to lock back very well so I guess the reason pulling vacuum helped was because it helped the cable to slide back.  My unit is white instead of black but it has the interlock built in so who knows.

If the picture in reply #9 is same one that is in your car then I can confirm that it is the correct 69 tilt bracket just with a switched out 67/68 vacuum canister. Regardless of color the vacuum canister itself functions the same.  At least you can eliminate the possibility of the wrong bracket as a issue.

[eric lipper]

I am not sure why the pictures of the engine compartment and a wide shot of the front of the car are included in reply #8 other then to showcase a beautiful car because they are unrelated to the tilt away issue. Not appropriate to comment on this thread given the subject matter but as you are apparently after historical correct presentation you may want to start a new thread with that in mind and ask about what is not historically correct under the hood and on the exterior in those pictures for fine tuning the historical look.That is if you are curious. If not disregard.

Bob I posted the photos because I think it is helpful for people to have some record of the car and equipment in which this tilt away is located.