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Any sure fire way to prevent hard top leakage after taking it off?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Madbomber88, Oct 14, 2002.

  1. Madbomber88

    Madbomber88 1/2 ton status

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    I'm sure this has been answered many times before, but I took my hardtop off for the first time ever on my 90 K5 last summer. Put back on in the fall and it has leaked in numerous places ever since even after patches with silicone and all that crap. Anyone have the problem of leaking around the side windows of the top? I tightened it to the cab first but I guess it didn't help. Today I took the top off again to start from scratch. The seals look ok, but I am thinking about replacing them all anyway since they aren't too expensive from LMC. Any sugestions that will work for sure? I'm going to try the armor all and see if it works.
    Thanks,
    -Tim
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    Armor all is bad for rubber that sees UV. (sun)

    No experience with it, but "vinylex" might be something to look into. Apparently doesn't contain silicone (which is again, the UV issue) so you might want to check into that vinylex, and see if it mentions rubber seals and gaskets.

    As to the sealing problem, GM has you bolt the top on a certain way. Of course, I ignore that, and bolt the cab to the top snug, then work from front to rear on the topper to bed bolts, which would tend to "squish" the gaskets front to rear, hopefully preventing any bulges.

    After all are snug, I then bolt the top to body bolts tight, then the same pattern for the topper to bed.

    Of course, my gaskets are really bad, and I'm missing one of the topper to cab gaskets, and the butyl "drain" directors near the cab pillars, so I have some leaks, but when I spent time making sure everything lined up, the leaks were much less.

    I'd say if replacing gaskets, the bed rail ones are worthwhile to replace, as well as the topper to cab seal that is exposed to the whether. As long as the inner one appears in good shape, is still soft, and hasn't "assumed" a different shape, I'd not worry about it.

    The butyl "drain" director my '86 body has, apparently is quite effective, I notice a fair amount more leakage on the side that DOESN'T have that, than the side that does, especially when parked on a hill with the nose uphill. This little strip of butyl is right behind the cab pillars, angling from the inside of the truck towards the taillights, if that makes sense. One side of it pulled apart when I pulled the top off of mine.
     
  3. imiceman44

    imiceman44 1 ton status

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    Well I guess I am lucky /forums/images/graemlins/smile.gif
    Mine is a 76 and I have FOUR BOLTS on.
    2 on each side bolted to the bed, none on the cab side and I have had no leaks in the past 2 years, even after I wheel the heck out of it and it squeeks a lot but still no leaks.
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    Be careful doing that, I'm not certain its 100% the cause, nor that using all the bolts will prevent it, but the caps will, and do regularly (if you look) seperate at the seams...too much flex will obviously make the problem worse.

    Even if it doesn't help to have more bolts in, it can't help to have less in. I know the tops aren't rigid enough to completely tie the body into one cohesive piece, but it certainly doesn't hurt to use all those bolts and the top to strengthen the body up.

    I've got three tops right now, ranging from about '78-86, and two of them are split at the seams. I doubt ANY of them were run with less bolts than stock, but if 66% of the ones I have (and many more that I've looked at) are split from flex, less bolts can't be helping any.

    My opinion of course, I think these trucks are too flimsy...
     
  5. fulltopblazer

    fulltopblazer 1/2 ton status

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    The top on my '74 has started to seperate at the back corners my door strickers also losen up after alot of hard wheelin. When I have the money I'm ditchin the hard top and going with a soft top only.
     
  6. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I used to use a thin film of vaseline on the rubber seals when I still cared whether or not my top leaked...it worked well and prevented the seals from tearing the next time the top was removed.

    Now that the cab is tweaked I'm just happy to get 4 or more bolts in without cross threading them/forums/images/graemlins/crazy.gif...and it still doesn't leak.

    Rene
     
  7. imiceman44

    imiceman44 1 ton status

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    I would have to disagree here.
    I think that what has kept my top intact was the fact I didn't use enough bolts, actually I bought it that was and never got around to getting more bolts for it.
    I noticed yesterday that actually 2 off the bolts are not even holding anymore, the holes are widened and the bolts are going through the holes, so there is no stress whatsoever on the top, I don't think it's a safe thing to have but it's working /forums/images/graemlins/smile.gif
    Well I think there is a way to minimize stress on the top, if you get longer bolts, a large washer and some rubber washers or bushings and tighten them without squishing the rubber. You would have a firm yet flexible top.
    Maybe I will try it and let you guys know what happens.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    I'm taking this from experience with the GM A/G bodies of 78-87. The B or C pillar will crack. They too have flimsy frames, with only the body to try and "strengthen" them, just like the K5. If you run "better" bushings (such as poly) you tie the body to the frame better, "tightening" the car up. Basically you are spreading the load over the entire body, not just on the corners. If someone doubts this works for trucks, I had my dads '74 on a weird incline, making the truck "twist" in the center. There was an admirable amount of flex between the cab and the bed...I'd say between 3-5 inches movement on one corner. Thats great to keep the wheels on the ground, however, I couldn't open the door. The problem is, the suspension should be keeping the wheels on the ground (articulation) NOT the frame.

    I don't think that was actually GM's intent though. Back in the day, they were using frame flex as a way to get a better ride, and/or better ground contact on the trucks. With the body firmly tied to the frame, there is the possibility of making the entire vehicle extremely rigid, and that let's the suspension actually do its job.

    The top is a structural component, albeit a weak one. Its got the rear steel "hoop" in it, and I'd guess there might be one up near the cab, but it would be less significant.

    Ask anyone that has installed a full cage tied to the frame in numerous spots, I'd bet the results are unanimous that the truck is MUCH tighter. Of course, if you let the body do all the flexing, then no, the top wouldn't crack. But of course, if you prevented the body from flexing, the top wouldn't crack anyways, and if the topper is helping to somewhat limit flex (its mainly fiberglass, fgranted, it won't help MUCH) then the overall flex of the truck body and frame is less.

    Ever wonder why some of the sheetmetal bolts are so hard to get aligned after being on for 20 years, even with no accidents? Ripped body mounts? Loose rivets? Cracked engine crossmembers? : )
     
  9. StiffRide81

    StiffRide81 Registered Member

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    Well, if you dont plan on taking it off again... you can use silcone sealant /forums/images/graemlins/thumb.gif
    That will definatley keep out the water! /forums/images/graemlins/grin.gif
     

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