| AC Cap found weak, I have a fix [message #356503] |
Tue, 07 July 2020 17:59  |
GatsbysCruise
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
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Working on the GMC, want to take it out for some testing, maybe a long distance test run at some point.
Still have to have that fuel tank problem that caused the power loss after the hoses were replaced but thats to come.
Was up on the roof, scoping the condition, found two concerns, The first was the AC Cap, the other is the Refer vent cap, more on this later.
The AC cap had cracks around the screws, also at the rear where the hot air is expelled, the top was cracked in two places. It was really in rough place. I was really careful taking it down, I was afraid it might break a big piece off just in moving it down to the ground for repair.
It stayed together and I looked it over well. It was ready for replacement if I didn't find a fix.
I am not one to give up on something that can be restored to an acceptable level for reuse so I was scratching my head.
I recall a show that used Truck Bed Liner (TBL) to strengthen a weak surface, it sounded perfect, paint it on, it cures over night to a more solid tuff surface.
The cracks needed more I thought. I found some cloth used over seams on roofing projects. You cover the surface that is cracked, lay the material on top, then saturate the material, it almost becomes invisible. Work the air bubbles out by pressing the cloth with a bit more TBL material so it is soaked up in the cloth. The air bubble should move to the edge and be gone.
I covered all the cracked areas, did both sides along the bottom that attaches to the base unit of the AC.
I did the inside of the cover on one night.
The cap has distorted some, the cracks are not sitting aligned and you need to use tape, and some leverage to get them back in position.
After 24 hours I coated the outside of the AC cap, using cloth where the cracks were. The TBL is clear so from the ground, the repair is basically invisible.
After 24 hours of curing, you could feel how much strength was restored into the cap. I was told the TBL coating would help prevent the cap from being smashed in hail storms, so thumbs up to that.
Put the AC cap back on and it looks like any other cap.
Not a bad project, took a couple days only due to cure times, made no visual changes at all and added strength to the cap body.
If I can remember where the other site is I will try to post some pics.
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
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| Re: AC Cap found weak, I have a fix [message #356513 is a reply to message #356503] |
Tue, 07 July 2020 20:46  |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Senior Member |
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I have done that for years using 2" wide 80% / 20% fiberglass (It comes n a roll) and epoxy resin. My most recent GMC project doing that was 3 GMC original Hammond vent covers.
I would be interested in exactly what products you used. Bed liner to me is Black and sprayed on.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: AC Cap found weak, I have a fix [message #356534 is a reply to message #356513] |
Wed, 08 July 2020 11:31 |
GatsbysCruise
Messages: 261
Registered: January 2017
Location: Waukegan, Illinois
Karma: 3
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Senior Member |
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Hi Ken
The Truck bedliner is clear, it does have a mild texture when cured but that texture is not noticeable. (Duplicolor CTBQ100 Truck Bed Liner)
The Cloth is " XFasten Fiberglass Waterproofing Anti-Fracture Membrane Fabric Tape, 6-Inch x 75-Foot, Water Barrier Mesh Tape for Shower Walls and Tiles". This is much like the cloth I had used for the old RV roof with the Elastocmetric rubber coating. It worked fantastic over the seams where the coach had some movement. (them old coaches really are not rock solid you know). Those seams is where the aluminum roofing coating failed and would leak.
The cloth is stuck on the space you want to strengthen then you work all the air out of the cloth so the material is completely covered with the TBL material. After that TBL material cures, the cap becomes very strong again.
The TBL material seems to be strong even without the cloth which thickens the TBL material which then cures to a semi rigid property.
I use the TBL material for a lot of things and have had very good luck with every project.
Thanks for your interest
slc
GatsbysCruise. \
74GMC260 Former Glacier Model style. \
Waukegan, Illinois \ Keep those MiniDiscs Spinning \ MY GREYHOUND IS FASTER THAN YOUR HONOR ROLL STUDENT \ WindowsXP-Win7-Win8.1-UBUNTU STUDIO - UBUNTU VOYAGER - Berzin Auto Center
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