Author Topic: ACC overhaul - Heater box / evaporator removal  (Read 25224 times)

ckamila

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ACC overhaul - Heater box / evaporator removal
« on: 30 January 2012, 08:43 PM »
I was going off topic on my previous thread troubleshooting a vacuum related shutdown issue which was traced to the defrost pod under the dash. http://forum.w116.org/mechanicals/removing-the-ccu-1980-300sd-engine-shutdown-problem/ But having dived into the climate control system i wanted to bring her back as best i could with a little (or a lot) of assistance along the way.

Heater box/evaporator removal - currently need to disconnect a/c lines at expansion valve, remove right side heater hose which is giving me fits and remove the last mounting bolts. I was able to disconnect the left hose with the help of my 13 year old son - him holding brass/copper tubing inside car while I was pulling/prying from the outside. How can such a small hose be SO difficult to remove from the tubing. I must be doing something wrong? the right side has even less room to maneuver heater hose but an easier grasp of the tubing. So i need a beefier helper or different technique?



Most everything out of the way and tagged where i thought necessary.
Think i still know where everything goes?

Chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #1 on: 31 January 2012, 10:04 AM »
Amazing!  I removed my expansion valve with regular wrenches but crow foot wrenches would have made the job easier. Pulling the round corrugated duct that runs from the center "stack" to the window vents made it easier but it looks like it may be out of yours already.

This will give you a chance to clean the evaporator and heater core as well as install a new expansion valve.

You may want to consider upgrading the AC hoses to modern barrier type if you plan on going with R134a.
« Last Edit: 06 February 2012, 07:27 AM by 1980sdga »
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #2 on: 31 January 2012, 01:31 PM »
Hi Jon - Not having done this before i am following the service manual and just removing things in my way including heater vent tubes. Maybe i will invest in a few crow feet wrenches too.

On the right side heater hose - access by way of removing grill below wipers - What is the best method for removal? It appears to be glued in place. The heater hoses appear inexpensive...should they be replaced or leaved if not cracked?


Left heater hose disconnected



Right hose still attached



Right side of heater box with tube causing holdup



Expansion valve ready to disconnect



Chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #3 on: 31 January 2012, 05:12 PM »
Looks like a PITA...  I see where you have removed the blower assembly.

Maybe try some penetrating lubricant around the metal tube and a blunt screwdriver worked between the metal tube and hose.  If there's even room for that...

The expansion valve is tough because you must work 2 wrenches in there in order to hold the evaporator tubing and prevent any kinking or breaking of the tubes. There is also the little equilization tube to deal with.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #4 on: 31 January 2012, 07:13 PM »
Don't you just love it when something clicks in your head - mine usually clicks in a little slower than it should  ::)

My previous post "maybe it's glued in place" was it. IT WAS GLUED or rather melted to the tubing. Grabbed a pair of vice grips and just gave the hose a little turn to the left and then to the right and i heard the rubber snap free. Took about 30 seconds including grabbing the tool. Can't believe how much time and effort wasted in trying to pull the hoses form the tubing. No matter how much i pulled it would not pull free. Good thing this is a hobby and not a profession!

Onwards and inwards to the expansion valve!

Chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

TJ 450

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #5 on: 01 February 2012, 05:20 AM »
Yes, the hoses often need to be twisted to remove. Some of them are almost impossible to remove.

Tim
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ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #6 on: 01 February 2012, 01:31 PM »
1980sdga - Jon, talk to me about the 

You may want to consider upgrading the AC hoses to modern barrier type if you plan on going with R134a.

Costs? Benefit over current (original) hose?

Chris
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #7 on: 01 February 2012, 05:28 PM »
If you're going to convert to r134a then it's a good idea to replace the hose.  The old hoses worked fine with r12 but r134a will seep through the rubber and you'll be recharging the system more often.  Barrier hose has a liner that keeps r134a in the system. If you are sticking with r12 (Which is hard to find, expensive, most AC shops won't use it, etc.)  then you may be OK with the old hose.

An AC shop could probably do it using your fittings with new ferrels.  Plus you're going to have the expansion valve out anyway and you are pretty deep in it now  ;D
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

koan

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #8 on: 01 February 2012, 11:16 PM »
If you're going to convert to r134a then it's a good idea to replace the hose.  The old hoses worked fine with r12 but r134a will seep through the rubber

Is that really the case?

It was suggested when R134A was introduced a lot of new bits would be required but in practice R12 bits work with R134A just fine, only in odd cases are any changes required and that's usually when the R12 system is only just cutting it.

Hoses are an example, theory has it that the smaller R134A molecules will seep through non barrier rubber hoses, but in practice an old oil soaked R12 A/C hose is impermeable to R134A.

koan
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1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #9 on: 02 February 2012, 06:26 AM »
Good input Koan!  I had never touched an AC system before last summer so most of my advise should be tempered with that in consideration  ;D

I believe the barrier hose was mandated by the EPA to address global warming (Or was it cooling back then  ???) rather than AC performance so messing with hoses may be overkill.  My AC was working fine on r134a before my compressor went south. My old hoses looked OK. 
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #10 on: 02 February 2012, 11:25 AM »
Koan and 1980sdga - Gentlemen, please keep the lively discussion going. The more feed back i have on this project the better!

KenM and jbarsile have stated (KenM seemed under duress at the time of his remarks ;)) that sticking with R-12 is the way to go for our older cars when possible, yet both tout the good cooling qualities of R-134a in a properly built and cleaned system. How long R-12 will be available in the States, who knows?

I need to replace the compressor  (frozen) and dryer too, so the system will be completely clean except for the hoses which have their own debated threads.
« Last Edit: 02 February 2012, 05:27 PM by ckamila »
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #11 on: 02 February 2012, 12:06 PM »
Had it been converted to r134a?  You can tell by the service valves.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #12 on: 02 February 2012, 05:21 PM »
No, all original, 3 owner car - 2nd owner did nothing and owned it for maybe a year before i got it.



I was a sucker for all that chromed trim, more interior room than my 85 300D and overall look with light gray body over black leather interior!


Chris

« Last Edit: 02 February 2012, 05:41 PM by ckamila »
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K

1980sdga

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #13 on: 03 February 2012, 07:41 AM »
I say stay with r12 if at all possible. The consensus seems to be that our AC systems work better with it.

Refrigerant threads are like oil threads and it all seems to come back to the bumpers  ;D

I was using r134a in my original system and it was cooling pretty well.
Jon


Little by little I have grown fond of the infamous Auto Temp II we have in our 116's

ckamila

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Re: ACC overhaul - Heater box / evaporator removal
« Reply #14 on: 03 February 2012, 04:06 PM »
Still making slow progress but finally i have evaporator/heat exchanger out!

Hey, Major Tom, if you're reading this thread please chime in on the type of foam you used to repair/rebuild your "airbox." So far your thread http://forum.w116.org/interiors-and-exteriors/airbox/ is the only detailed info i have found. Any help would be welcomed.

Joe, If you are around...what rubber bits are available for replacement for this overhaul? The rubber grommets between cabin and wiper area (?) are hard and cracked. Also between firewall and wiper area - especially the right side above exhaust manifold.






There's that missing floor vent pod - i knew it was somewhere.



Evap/heat box and lower vent section



What should i used to clean up the oil tape residue off the expansion valve? Anyone?


Disassembling evaporator hopefully starts tonight!

chris
« Last Edit: 06 February 2012, 11:09 AM by ckamila »
If it's not broke i haven't fix it yet...


1980 300SD, 170K
1985 300D, 235K