1977 NYB Cruise Control

[Rusell Petry]

I have the complete cruise control and it worked a little for a few rides after I get the car in 2021. I say it worked a little bit because it tried to keep the speed where I set it but ended up not. I pulled a vacuum on the diaphragm on the cruise and it is definitely leaking in the diaphragm. Question is are the diaphragms still available somewhere? I would love to have it working if that is all that is wrong with it. Thanks in advance!

 

[thethee]

IIRC, @Ross Wooldridge might have a source on those diaphragms.

 

[Rusell Petry]

IIRC, @Ross Wooldridge might have a source on those diaphragms.

Thank you and Happy New Year!

 

[thethee]

If you can pinpoint the leak on the diaphragm, I've had some luck with a bicycle tire repair kit

 

[Rusell Petry]

If you can pinpoint the leak on the diaphragm, I've had some luck with a bicycle tire repair kit

Hmmm, I never thought about that option. I will try to figure out if that will work while I have the car all apart for EFI upgrade. Thanks.

 

[75LandYacht]

Hmmm, I never thought about that option. I will try to figure out if that will work while I have the car all apart for EFI upgrade. Thanks.

EFI!!! Ewwww keep me posted, cause I may do the same. Start a thread for cry’en out loud. Lol

 

[Ross Wooldridge]

My "source" makes them new in reproduction, but he's currently without a shop facility, and I don't know when he'll be back in business.

 

[Boydsdodge]

My cruise was not holding vacuum, so I opened it. Diaphragm was in good shape. I think it was a mechanical/ electrical problem. There is reed valve on the vacuum inlet hose of the servo, I think it gets stuck open keeping servo from holding vacuum.

 

[thethee]

My cruise was not holding vacuum, so I opened it. Diaphragm was in good shape. I think it was a mechanical/ electrical problem. There is reed valve on the vacuum inlet hose of the servo, I think it gets stuck open keeping servo from holding vacuum.

More likely to be a problem with your vacuum dump valve. The reed valve you mention is only to open and close the source of vacuum to the chamber. If your diaphragm is good you should check the o-ring underneath your dump valve and also the gasket on the side where speedo cable is mounted. If those check out you'd have to benchtest the dump valve. Could also be an issue with your brake switch though

Edit: same goes for the OP of course, there are several places for vacuum to leak in these things