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-   -   Crazy popping sound underneath. (https://67-72chevytrucks.com/vboard/showthread.php?t=14195)

barn9 05-30-2002 08:07 PM

Crazy popping sound underneath.
 
At first I thought it was a U-joint or the carrier bearing, but a couple times when just getting into the truck, I hear this loud pop. I crawled under yesterday and noticed that the driver side cab mount looks a little funky and it made me wonder if that rubber being a little collapsed could let something move enough to make that popping sound. It sounds like a metal on metal pop to me. Anyone ever had anything comparable? Or should I just start replacing U-joints and posssibly the carrier bearing. They do all have some age and miles on them, so I'm thinking of just going through and changing them anyway. But the popping is making me scratch my head as to the cause. Thanks for any insights you guys might have, LB. :bowtie:

Fast68Chevy 05-30-2002 09:53 PM

cab mount popping makes ore sense than anything else, why would anything else pop wen you just get in the truck :confused:

BLACK AND BLUE 67-72 05-30-2002 10:27 PM

Is it 4 Wheel Drive? If so it could be the front leaf spring bolt hitting the inner fender well and popping off the edge. If 2 Wheel Drive it could be a cab mount or suspension related.:flag:

barn9 05-31-2002 01:06 AM

It's 2 wheel drive, and the sound seems to be coming from area under back end of the cab. I went back and forth a few times in the street with my neighbor walking alongside, and then he drove while I listened, and (murphy's law) not a fricken peep! I have never changed or even touched a cab mount before, any tips would be appreciated! Just from the look of it, I wouldn't think it needs replacing, even though it shows age, but if that turns out to be the problem, it will be done. :bowtie:

68 Stepside 05-31-2002 01:16 AM

rear trans mount ok? just an idea.

Big69C20 Toy 05-31-2002 01:17 AM

cab mounts are easy, one of the first thing i did on my truck, even though it didnt need it. Just undo the bolts and stuff should come out. yer bolts might be fubar (hope not) cuz the kit i bought didnt come with new bolts. Anyways just get a nice wood block on yer jack and loosen all the cab mounts, lift one side up and switch out bushings, easy stuff! then follow same on other side.

OhioDan 05-31-2002 03:40 AM

I had a dry ball joint one time that would make a popping noise. Shot some grease to it, and the popping went away. My $.02

Tink 05-31-2002 07:11 AM

The cab mounts on my S10 were bad... (they looked squished) and it would make a popping sound that came from the rear of the cab.

BigJackDaddy 05-31-2002 08:56 AM

How do the shock bushings look?

texnician01 05-31-2002 10:45 AM

it wouldn't surpise me if the cab mount rubber was soft and the pop that you hear is the theads on the bolt rubbing against the frame or the washers as the mount compresses. take a piece of sheetmetal and run the threads of a bolt across the edge of the metal. see if it makes a simmilar sound.

Nathan

barn9 05-31-2002 11:02 AM

Really appreciate the help guys! Front end parts, shocks, etc. are all in excellent condition and well maintained. The cab mount is the prime suspect, but I'm going to give the U-joints a close inspection, and check tranny mount, etc. just to be sure. Where's the best place, read that best price, to get cab bushings? Thanks again everyone, it is so great to have this board for these situations. :bowtie: :bowtie: :bowtie: :bowtie: :bowtie:

Southpa 05-31-2002 01:22 PM

I had similar noises coming from underneath years ago, mostly while turning out of my driveway. It turned out to be one of the frame crossmembers needed to be tightened up. If you DO find that is the problem, take the offending bolt out and inspect it for wear, also the edges of the hole where it came from.


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