Author Topic: I bit the bullet... HVAC refurb  (Read 4726 times)

TJ 450

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I bit the bullet... HVAC refurb
« on: 21 December 2009, 05:38 AM »
Yes, I decided it had to be done, so I removed it. Now that I have full access, I will repair everything in sight and have new A/C hoses made up to fit as well.

Again, removing the dash results in some damage in the LH corner, where the material tucks in forward of the A-Pillar. Fortunately this is not visible when installed, but it would be interesting to know who has removed a 116 dash without this problem.



Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

s class

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Re: I bit the bullet... HVAC refurb
« Reply #1 on: 21 December 2009, 06:03 AM »
Dash removal projects present the strongest case I know of "while I'm in there".

Well done.  I know you have done a W126 dash before, but is this your first W116 dash?  How long did it take you to get out?

'76 6.9 Euro, '78 6.9 AMG, '80 280SE, '74 350SE, '82 500SEL euro full hydro, '83 500SEL euro full hydro , '81 500SL

TJ 450

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Re: I bit the bullet... HVAC refurb
« Reply #2 on: 21 December 2009, 06:19 AM »
It took about four hours to remove everything. This is indeed the first 116 dash I've removed myself, though I assisted Major Tom remove his, so I already knew how it came apart.

"While I'm in there"... yes, that is absolutely the case. I won't get too carried away, though. The main thing I'll do is treat and repair that rust, which is no longer active fortunately and replace a few grommets and the A/C hoses. 8)

The 126 dash is easier to remove, but only marginally so.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

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Re: I bit the bullet... HVAC refurb
« Reply #3 on: 21 December 2009, 07:00 AM »
hope you have better luck finding suitable adhesive foam, ive been everywhere today and came up with stuff all.

I have some and have done the fan motor housing, but thats it, its too hard for the delicate airbox flaps, will be interested to see what you come up with.

I do have however a bulk pack of bitumen tape for wrapping TX valves and internal pipeworks to prevent condensate dripping, which is an essential part of the reassembly.

TJ 450

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Re: I bit the bullet... HVAC refurb
« Reply #4 on: 21 December 2009, 07:12 AM »
I would just use standard foam with contact adhesive. As far I can see, that's how it was done originally. It's pretty thin foam though.

The bitumen tape sounds good. I noticed that my TX valve was replaced as part of the R134a conversion and the fittings are imperial.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

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Re: I bit the bullet... HVAC refurb
« Reply #5 on: 21 December 2009, 07:15 AM »
I would just use standard foam with contact adhesive. As far I can see, that's how it was done originally. It's pretty thin foam though.

The bitumen tape sounds good. I noticed that my TX valve was replaced as part of the R134a conversion and the fittings are imperial.

Tim

134a,  frikken hippies  ::) refrigeration flare connections are always imperial, well they were when i worked in the industry.

Where do you buy this standard foam from, ill get some tomorow. I still havent worked out how the hell im going to refoam the lowest removable section flaps for the front and rear foot vents. This section isnt servicable without drilling out all the rivets and slicing away the glue. But it will be done.

TJ 450

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Re: I bit the bullet... HVAC refurb
« Reply #6 on: 21 December 2009, 07:21 AM »
There's a place "south of the river" that deals with all sorts of foam. I'll have to have a look at what they've got.

Yeah, 134a, what a load of propaganda! 8)

I don't know about the bottom section, I haven't looked at it yet.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

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Re: I bit the bullet... HVAC refurb
« Reply #7 on: 21 December 2009, 07:28 AM »
your going to need to be more specific, I only have this week to refoam my box ;)

Where the hell is this place, or if your going, buy me some too ;)
« Last Edit: 21 December 2009, 07:37 AM by Major Tom »

TJ 450

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Big_Richard

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Re: I bit the bullet... HVAC refurb
« Reply #9 on: 21 December 2009, 07:41 AM »
heh, i know exactly where they are, i have a client 2 numbers up the street  8)

I might go for a nosey tomorrow.

Cheers!

koan

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Re: I bit the bullet... HVAC refurb
« Reply #10 on: 21 December 2009, 08:23 AM »
Again, removing the dash results in some damage in the LH corner, where the material tucks in forward of the Pillar.

What kind of damage?  Did you remove the A pillar trim?

The trims are not hard to remove, I had one off when running a wire to the interior light for alarm sensing (long story won;t go into details).

(Collecting info for when I make the commitment)

koan
Boogity, Boogity, Boogity, Amen!

TJ 450

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Re: I bit the bullet... HVAC refurb
« Reply #11 on: 21 December 2009, 08:37 AM »
Everything was removed, it's the shape of the dash itself that's the problem. It curves in, in front of the A pillar, so that the dash is wider than the largest distance between both A pillars.

Something has to give, and it ends up with the plastic ripping or cracking in that area, which is unacceptable, but it happened. I haven't worked out a way around this.

When I get a chance, I'll take a photo of it.

Tim 
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

wbrian63

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Re: I bit the bullet... HVAC refurb
« Reply #12 on: 21 December 2009, 11:15 AM »
The instructions from the W116 service manual say to press the corner of the dash opposite the steering wheel downward with a plastic wedge to allow it to be pulled out into the cab.

I can only guess this wasn't a big deal when the dash's were new in the box. On the 6.9 I'm parting out, I wanted to pull the dash intact so I could send it out to be refurbished for #521. Even with the windshield out, the amount of damage to the corner of the dash was enough that I decided it was better to junk it instead of trying to have it recovered.

I don't know what I'm going to do with the #521 dash when it comes time...

Parting out #1164 has yielded valuable "proper way to do it" information regarding a variety of removal issues, that should pay dividends when it comes time to do the same work on #521, assuming I can remember what I did on #1164 when the time comes...
W. Brian Fogarty

'12 S550 (W221)
'76 450SEL 6.9 Euro #521
'02 S55 AMG (W220) - sold
'76 450SEL 6.9 Euro #1164 - parted out

"Bond reflected that good Americans were fine people, and most of them seemed to come from Texas..." Casino Royale, Chapter V

oscar

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Re: I bit the bullet... HVAC refurb
« Reply #13 on: 21 December 2009, 03:15 PM »
The instructions from the W116 service manual say to press the corner of the dash opposite the steering wheel downward with a plastic wedge to allow it to be pulled out into the cab.

That's interesting, I don't remember trying that.  I just wonder how far you have to push.  I've only had the one opportunity to learn from a car I wrecked and suffice to say I couldn't get the dash out unscathed, even with roof, doors and glass removed.  I left about 3" of A pillar standing still to simulate a car intact but it was just too tight.  I wonder if the dash foam hardens and prevents an easier release and refitment.

Regarding foam TJ&MT, maybe a suggestion.  It seems this xmas I'll be taking on a new hobby, RC planes ;D using my 11yo as an excuse to finally get into it.  Anyway, all the foam planes from cheapies to quality ones have foamed and taped hinged control surfaces.  If there's a good RC place around Perth, which I know there will be, it might be worth going in there and having a look at their adhesive tapes.  Basically whatever they would use to repair or build hinged joints for ailerons etc.
1973 350SE, my first & fave

Big_Richard

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Re: I bit the bullet... HVAC refurb
« Reply #14 on: 21 December 2009, 04:08 PM »
on my 6.9 there is evidence of friction reducing black Teflon coated tape coated with some now non existant grease on the A pillars where the dash slots in. I've always been of the opinion that dash removal / installation on these cars only went smoothly when the cars were new and the dash's were soft. Now after 30 years every single one of them will be hard and crusty ready to crack at the first opportunity.