Did I mention that my car is angry at me? Vacuum leak from gear selector....

[King_V]

I think both lines were black going into mine.... though I was more swearing at the funky yoga positioning, tight access, and inability to maneuver the flashlight - but I don't remember any white vacuum lines...

[sly]

oh well... since it's just 2... it's still easy enough... the white one should be the one that's NOT going to the firewall from the valve. If yours are both black... then you know which one is which. change instructions accordingly.

[King_V]

Ok - so, what's the proper behavior of this u-shaped vacuum valve new?

There's the vacuum input (marked B) and vacuum output (marked S).

I put a vacuum cap over the S-port, and then attached a vacuum pump to the B-port.

With the slider moved to direction, it holds vacuum. If I pull the vacuum off the S-port, then the vacuum goes to 0. Obviously this would be the case when the car is put in gear.

But if the slider is moved in the other direction, with the vacuum cap on the S-port, the valve doesn't hold any vacuum. Is this normally supposed to have a slow (controlled) leak when the car is in Park, Reverse, or Neutral? Or is my new U-shaped valve defective?

(the old one, by the way, simply never holds vacuum regardless of position, with the vacuum cap on the S-port and the vacuum pump on the B-port).

[sly]

yes, this is normal. It shouldn't hold vacuum in park, reverse or neutral. It should hold in any drive setting.

when you install it, there's a little adjustment play... you may need to move it so that full range of movement can be achieved.

[King_V]

Thanks, I appreciate it! Just wanted to be sure I wasn't mistakenly assuming it was defective.

[King_V]

By the way, in my diagnostic attempt - I'd gotten the source and the output reversed.

Vacuum source goes to the S-port (small) - and vacuum output, to the actuator, exits via the B-port (big).

Ah, so my vacuum pump testing was incorrect. Well, what it did show me was the behavior of the two (old vs new) parts was different, thus confirming the source of the problem.

It seems that when vacuum is applied to the source port, it does NOT leak out anywhere - I was mistaken about that. When I tested the new one correctly, no vacuum leakage at all, controlled or otherwise.

Getting the thing back in with those two tiny hex screws in tight confines was . . . unpleasant. Much swearing and ranting about how such a big car can have so many things so awkward to get to was heard by anyone who might've watched me do this job.

At least I was able to get the positioning correctly so that the brake releases whenever I put the car in any forward gear. Previously, and this had been the case since I first got the car, it would be hit or miss as to whether shifting to overdrive would release it, though Drive and 1 would work fine.

[onedollarbob]

Previously, and this had been the case since I first got the car, it would be hit or miss as to whether shifting to overdrive would release it, though Drive and 1 would work fine.

Yeah, same on mine when it wore out . . . probably from getting out of adjustment. Something about the new part when I got it installed is now my column shift is super light. Before, shifting was overly stiff with heavier detents between gears.

[King_V]

*sigh* . . well, let's see about doing the math here.

Factory U-shaped vacuum valve for this lasted from 1987 until about July 2013.

New replacement part lasted from late July 2013 to late October 2013.

Yeah... the math says the new parts suck.


At least it's under warranty, but still..... Hopefully that was just a fluke, but if it fails again, I'll just not bother, and get my money back. It's a shame, though... if the new ones are really THAT shoddy.

[GM_Guy]

That valve was probably sitting on a shelf getting old for 10-15 years already.

Alex.

[King_V]

Well, finally stuck the new one in Thursday night. Definitely something satisfying about that brake-release thing working right again, even though it's just a silly little feature that I could live without!

I'm really hoping that the valve will hold up this time.