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I was only trying to point out this common cause of vacuum leaks.
When someone asks a question I try to walk them through the diagnostics. So everything in the engine bay at a glance first. Then on to tearing into the dash Then the troubleshooting pages from the EVTM. I well know the most likely culprits. I start with that before I dive into a rabbit hole.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
In reply to this post by mat in tn
I assume vacuum switch you refer to is what I call the manifold, (pic attached), on the right side of the control head? I will try to check each pot vacuum line from the pot to the manifold while moving the control lever through the different positions and note if vacuum stays steady or bleeds off. I appreciate the help!
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
In reply to this post by ArdWrknTrk
At my age, 71, I appreciate everyone's replies and advise. I can't lay across the floorboard like I did years ago. Don't know what possessed me to buy the bullnose, but I have no regrets other than I need more money than I got. LOL. As I find issues, you guys are helpin' me to repair them. I appreciate everyone's replies and advise.
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
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In reply to this post by CDLong
He's talking about the selector in the climate control panel.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
So I will need to replace the first attached pic, climate control panel or the second attached pic, what I call the manifold, (the black and white part)? Either way, it's gonna be a booger.
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
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Mat already said what you have circled is likely a stud with a tin nut holding the thing together.
The "switch" is the valve that lever connects to, that directs the vacuum to the various flaps/doors in the ductwork. It's represented in the EVTM drawings Gary posted. If the system holds a reasonable amount of vacuum you don't have to replace anything.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
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In reply to this post by ArdWrknTrk
Do you want me to find you threads that show what fails and how to fix it???
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
That would be a big help 'cause I forgot my map & compass. In other words, I'm lost.
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
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Here's a few to start.
If you use the search function to look for "blend door" more will turn up. https://forum.garysgaragemahal.com/HVAC-Doors-help-tp81810.html https://forum.garysgaragemahal.com/Blend-door-repair-question-tp57653.html https://forum.garysgaragemahal.com/Improved-HVAC-blend-door-as-discussed-on-forum-recently-tp130679.html https://forum.garysgaragemahal.com/Heater-Blend-Door-Alternate-Design-tp112193.html
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
You did a bang up job Jim, thanks a million. I would never have understood what ya'll were talkin' about without these threads. I did do a little something, anticipating removal of the climate control panel, I found these: https://www.youtube.com/watch?v=3DbIjxCfJms https://www.youtube.com/watch?v=HPJj9pY3D3s
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
In reply to this post by CDLong
of course, some pictures can be deceiving, and angles make that worse. but looking at the switch in the picture, the one with the switch with the clear vinyl manifold and vacuum lines. the amber plate which is snapped onto the black body of the switch looks bowed to me. very common over time and heat cycles. 140 interior temp is not unusual in the summer sun. not a diagnosis. but if you were to follow the vacuum line over in front of the glove box. there is a pair with a coupling about 8-10 inches from the firewall. this coupling can be carefully disconnected and with the engine started, tested for vacuum. only one will have vacuum as it supplies vacuum to the switch yet the other is coming from the switch to the fresh/recirculate
damper servo. |
My fresh/recirculate damper servo, (the one in the engine compartment), operates correctly, so I have vacuum to it. I've only started reading the threads Jim sent but I have noticed several posts state their servos inside the cab are working. None of my servos inside the cab are working. I can operate them manually. I'll try to get the vac manifold with the clear hose connectors cleaned off and better photos of it. Don't know if this means anything but I notice the black plastic is not touching the white controller and the dirt has gaps?
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
i believe that you have narrowed the path. in the first picture it is very clear to see the amber colored plate has a crack about mid-way. this can be a vacuum leak.
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Thanks Matt, I have a 12-volt auto vac with very small attachments. I'll get the panel out I'll get it cleaned up and see if it can be patched. More pics to come.
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
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We can't easily get methylene chloride any more, but this is an ideal solvent weld for cracks in most hard plastics.
(source: My father was director of engineering for multiple plastics companies throughout my childhood and I'm a geek for adhesive chemistries and material science)
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
I was thinkin' duct tape? LOL
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
Administrator
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How about crazy glue?
The gel kind so it doesn't wick inside and freeze up the switching parts. I could tell you about optics and the discovery of Eastman 910, but I tend to get too tangential.
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
I'm thinkin' Flex Seal tape. I have used it around my shed in several spot and it works.
CD Long Jr
1985 F150 XLT Lariat 302 EFI AOD transmission 4x4 regular cab LWB |
Administrator
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Well, good luck!
Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake. Too much other stuff to mention. |
replace the switch! please?
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