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Floor penetration caulk

June 29, 2014, 11:44:56 pm

I have to run air lines from the front and rear brake tanks up into the dash area so that I can replace the failed electric air pressure gauges with mechanical ones.  So holes in the floor.  I also have to run some wiring into the Aquahot bay from the LR.  More holes.

Does anyone know what the white sealant they use at the factory is?  I am pretty sure it is not silicone but have no idea what it might actually be.

Thanks

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Re: Floor penetration caulk

Reply #1 – June 30, 2014, 12:08:47 am

I'd be willing to bet that it's 3M 5200 or something awful similar.

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Re: Floor penetration caulk

Reply #2 – June 30, 2014, 12:18:05 am

No, I would never use 5200.  It is permanent. 

4200 would be a better choice.

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Re: Floor penetration caulk

Reply #3 – June 30, 2014, 10:49:50 am

Yes 5200 is forever. I would probably have gone with that, and not thought of it again till it came time to replace that airline and thus buying additional trouble. However I don't feel bad about using that stuff to bond the dash plywood to the nose cap. I might even stay with 5200 for this application, and hope to not have to mess with the lines once the job is done. But I'm kinda dumb that way, not wanting to do a job more than once. But yes 4200 would give you some easier options.

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Re: Floor penetration caulk

Reply #4 – June 30, 2014, 01:48:31 pm

4200 fast cure seems to be much more usable in all cases. 5200 take FOREVER to cure and it oozes all over the place (dang gravity) until it finally does cure.

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Re: Floor penetration caulk

Reply #5 – June 30, 2014, 07:36:10 pm

Hi Roger,

Have you considered running your lines through the steering column hole then possibly sealing it a little better with air conditioner tape/putty.

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Re: Floor penetration caulk

Reply #6 – June 30, 2014, 08:04:34 pm

I was thinking that the air lines went to the blue box and that you could t off of them for the gauges, maybe just dreaming about that one.

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Re: Floor penetration caulk

Reply #7 – June 30, 2014, 10:29:01 pm

Well lots of folks thought it was the Blue Module.  Barry Beam sent me a picture of his.  There is nothing like that on my coach.  Must have started a few build numbers down the road.

I do have pressure transducers on each tank (both tanks near the front, thankfully) with a wire from each running up to a gray box labeled "988L controller" wire bundles run out from the gray box to each of the dash instruments. 

The line for the fuel sender and each of the pressure senders all measure a low voltage level to ground.  The air tanks were about the same, the fuel tank different.  These senders are likely variable resistance devices.  The more fuel or air pressure the higher the voltage.

There is voltage at the plug that goes into the gray box but nothing gets through to the aiar gauges.  They swing back and forth when the ignition is turned on but nothing after starting except for the red light and the annunciator (now silenced with a switch.)

Blue modules are no longer available, likely not the gray boxes either.  Two nice VDO gauges with install kits (tubing and fittings) were a bit over $90 with shipping.  Even if there were a gray box available it would be much more.

Air lines could come up through the hole where the steering column goes through.  There is a rubber grommet there that doesn't seal all that well.  It needs to be sealed up anyway.

If you ever have a chance (or need) to get behind the dash you will find a huge mass of wires and dozens of cable ties holding it all tightly together.  Pretty hard to follow any one wire very far before losing in in the jungle.  I need to get one of those electronic wire tracers. 

Every project is an education.

Roger

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