Photos of my A/C rebuild + timing cover reseal

E28 technical advice asked and given! Troubleshooting, modifications and more.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Here are a few pics of the work I did last week. The A/C worked, but I was getting air leaks from the heater box (most annoying was a whistling sound at speed, with flaps closed) and the compressor was starting to get noisy.

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The foam around the heater core had turned to dust, allowing the core to rattle about.
I'm sure this caused a large air leak on the left side of the box.

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According to the PO's receipts, somebody took the evaporator out in 2003.

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Next thing to do is a timing cover reseal and I'll take the wing cell compressor apart.

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Last edited by Federico on Sep 17, 2019 9:14 AM, edited 1 time in total.
HayekFan
Posts: 368
Joined: Aug 19, 2011 8:20 PM
Location: AL

Re: Photos of my A/C refresh

Post by HayekFan »

That looks great! Are the foam pieces still available?
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C refresh

Post by Federico »

HayekFan wrote:That looks great! Are the foam pieces still available?
Thanks!
I used foam from McMaster for the rebuild:

Flaps: 86225K51 Flame-Retardant Super-Cushioning Foam Sheet, Polyurethane with Adhesive-Back, 24" x 24" x 1/8"

Core & Misc.: 8709K58 Flame-Retardant Super-Cushioning Foam Strip, Polyurethane, with Adhesive, 2" Wide, 3/8" Thick, 50 Feet Long

Note the 2" strip turned out to be too wide; I cut it down to 1".
Bonsaibacker
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Location: Palatka FL

Re: Photos of my A/C refresh

Post by Bonsaibacker »

That is eye candy! Great job!
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Some more pics:

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The 46mm socket needed for the front wheel hubs is just right for pushing this seal in:

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I then tried to mount the lower cover in place, but it wouldn't fit. Only then I learned the gaskets are oversize and need to be trimmed to fit :P
Brown sealer is Permatex Aviation.

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For the Jesus nut, I used the La-Z-Boy (TM) technique. Before spinning the nut off, I scribed it and the hub:

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When putting it all back together, a short burst with the impact left the nut like this:

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So I just kept going till the marks lined up again.

It's not cheating if you cheat the cheater bar :laugh:
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Next up: The wingcell compressor

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I can already see rust through the ports :? While it had an annoying vibration just above 2000 RPM, it pumped and cooled well so I'm hoping it can be rebuilt.
Ju@n
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Joined: Apr 27, 2013 1:11 PM
Location: Uruguay

Re: Photos of my A/C rebuild + timing cover reseal

Post by Ju@n »

disassemble it (change all seals/orings), clean it, put some oil into it, spin it and offer it up to the car :D
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Ju@n wrote:disassemble it (change all seals/orings), clean it, put some oil into it, spin it and offer it up to the car :D
I think you've watched too many Overhaulin' episodes :laugh: :laugh:

Old oil with bits of foam:

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Bolt was spun off with the impact:

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I first tried to remove the hub by spreading the clutch, but there was too much flex. This was more effective:

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Now comes the disgusting part:

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Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Some more pics:

Shaft key is press fit, so I used this old grandfather tool (a sharpened valve stem) as a chisel to push it out.

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After a quick degreasing, it looks much better:

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So, I had 2 main issues with this compressor:
1. A high-pitched screeching noise just above idle, which started recently.
2. A distinct vibration just above 2000 RPM. The compressor ran like this since I got the car ( 6 years).

By the looks of it, the screeching sound was probably just the gunky clutch slipping. Maybe related to the leaky crankshaft seal too.

The vibration is most likely due to the vanes. The rotor and bearings are in excellent shape, but the vanes do have a few spots of rust. I think I'll just lap them gently before reassembly.
ARico08
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Joined: Jul 27, 2017 9:00 PM
Location: Mesa, AZ

Re: Photos of my A/C rebuild + timing cover reseal

Post by ARico08 »

Great stuff! I've actually got a compressor I've been wanting to rebuild so this is great reference material.

Where did you find the seals for the compressor? I can only seem to find generic kits that don't look like they would work.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

ARico08 wrote:Great stuff! I've actually got a compressor I've been wanting to rebuild so this is great reference material.

Where did you find the seals for the compressor? I can only seem to find generic kits that don't look like they would work.
I got an assortment of seals/bearings from JCS a year or two ago:
http://www.mye28.com/viewtopic.php?f=4&t=142973

Also, if you google with keywords like Bosch Behr Wing Cell Compressor you can find part sources, but you do need to scroll though a couple search result pages to find them. i.e.:
https://www.ackits.com/santech-compress ... r-wingcell

Also note there are different iterations of the wingcell. Mine seems to be the simplest, with only thrust bearings at either end of the rotor. The shaft rides on a bore machined into the cast iron cover (bottom right in the last photo).

At this point the compressor is ready for reassembly; I just need to find time to go buy oil for it. The OE Suniso 5GS mineral oil seems to be readily available, but I'll try to find a suitable POE substitute.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

I haven't had much time to work on this, but at least the compressor is now ready. I also serviced the aux fan motor while I flushed the condenser.

I was able to find the correct foam for the rear of the compressor and then carved a puck out of it, guesstimating the correct size:

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After putting the compressor together I noticed this metal insert was not seated all the way in, so I took it apart to make it right.

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New screws:

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I decided to remove 2 of the 4 spacer shims from the clutch. Yes, the compressor inlet had those 2 orings stacked together :laugh:

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I then went outside and flushed the condenser with isopropyl alcohol. Also, I took the aux fan motor apart since it felt gritty.
The motor has a bronze bearing at the rear, and an open ball bearing at the front. The latter felt dry and dirty, so I flushed it with solvent and then pushed some fresh grease through it. I used a marker to plug the inner race and then pushed the grease from behind until it oozed out clean at the front.

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jocal
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Joined: Sep 30, 2019 5:03 AM
Location: Philippines

Re: Photos of my A/C rebuild + timing cover reseal

Post by jocal »

Great write up on the rebuild. Question: are the heater & AC fan motors interchangeable?
tn535i
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Location: Middle Tennessee

Re: Photos of my A/C rebuild + timing cover reseal

Post by tn535i »

Good stuff. I once rebuilt an e30 compressor. Was having trouble with the AC and I found too much pressured drop across the R/D. I think that foam had disintegrated and most of it ended up in the R/D causing restriction. Maybe I missed it above but you ARE replacing that aren't you?

What will you re-charge with ? Regardless I suggest you test the system first with R12a, the hydrocarbon stuff and see how it works :)
Bonsaibacker
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Location: Palatka FL

Re: Photos of my A/C rebuild + timing cover reseal

Post by Bonsaibacker »

Great documentation. Thanks!
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

jocal wrote:Great write up on the rebuild. Question: are the heater & AC fan motors interchangeable?
I heard they are, but the AC blower's shaft has flats machined into it and the new heater motors that come without cages don't. It should still work though.
tn535i wrote:Good stuff. I once rebuilt an e30 compressor. Was having trouble with the AC and I found too much pressure drop across the R/D. I think that foam had disintegrated and most of it ended up in the R/D causing restriction. Maybe I missed it above but you ARE replacing that aren't you?

What will you re-charge with ? Regardless I suggest you test the system first with R12a, the hydrocarbon stuff and see how it works :)
Yes, I'm fitting new foam. I believe it is there to stop too much oil from being blown out of the discharge port every time the compressor pulsates.
Also, I have a PO's receipt from 2003 showing A/C work done on the car. Most of the perished foam must have been taken away when they replaced the R/D.

My 528i had R12 when I purchased it back in 2013, and it blew aim-the-vent-away-from-yourself cold. But it lost performance after 2-3 years so I took it to a shop that evacuated and recharged it with MO49 (R-413a). Performance was ok, but not quite as good in high load situations (i.e. car parked in the sun). Also, I have my doubts about the quality of the work. The system might have been undercharged (sight glass always had lots of foam, even in cool weather), and they also said they "tightened" one of the leaky condenser fittings. Now I learned that those are o-ring fittings, so no amount of tightening will get rid of a leak :laugh:

I will first charge it with MO49 Plus (R-437a) since it's very easy to get here in Argentina, and I'll be on the lookout for R12. R12 seems to be tricky to find here. I do see the large 30lbs canisters for sale every now and then, but always far from home. We'll see how the MO49+ handles this summer.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

Success!! :D :D
Yesterday I pressure tested the system with Ar/CO2 mix, pulled a vacuum and charged it with MO49 plus.
The retrofit guidelines call for an 85% initial charge (relative to R12) with a max of 95%. This early 528i holds 1300 grams and I think I got around 1200/90% of charge with the MO49.

Weather was mild: 22ºC/72ºF and 30% humidity

After filling about 900 grams I was getting 3ºC/37,4ºF at the vents with the blower full blast.
At that point the dryer was full of liquid, and I decided to keep going until I hit the 1200g mark. That was when I noticed the suction line coming from the firewall had a bit of condensation and with 20/200 psi displayed on the manifold, I thought it was enough.

Also, It looks like fixing the climate control grounds has paid off: http://www.mye28.com/viewtopic.php?f=3&t=152458

At full blast and with the vent temperature at 3C/37F, the compressor remained engaged constantly.
Reducing the fan speed to "I" dropped the temperature to 1C/34F, and the compressor would then start cycling :D

I have yet to test it on a properly hot day, but so far it's promising.

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demetk
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Re: Photos of my A/C rebuild + timing cover reseal

Post by demetk »

Very nice. Congrats. Environmentally how bad is MO49 plus? R152a has negligible environmental impact.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

demetk wrote:Very nice. Congrats. Environmentally how bad is MO49 plus? R152a has negligible environmental impact.
For MO49 plus the ozone depletion potential is 0 and the global warming potential is 1684 (R134a=1410; R12=8500), so pretty decent.
The actual blend is as follows:

78.5% R134a
19.5% HFC-125 Pentafluoroethane
1.4% Butane
0.6% Pentane
ARico08
Posts: 60
Joined: Jul 27, 2017 9:00 PM
Location: Mesa, AZ

Re: Photos of my A/C rebuild + timing cover reseal

Post by ARico08 »

Federico wrote:
demetk wrote:Very nice. Congrats. Environmentally how bad is MO49 plus? R152a has negligible environmental impact.
For MO49 plus the ozone depletion potential is 0 and the global warming potential is 1684 (R134a=1410; R12=8500), so pretty decent.
The actual blend is as follows:

78.5% R134a
19.5% HFC-125 Pentafluoroethane
1.4% Butane
0.6% Pentane
Where did you pick up the MO49? I switched my AC to RedTek R12A and haven't been thrilled with the performance but I can't find anywhere to source the MO49.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

ARico08 wrote: Where did you pick up the MO49? I switched my AC to RedTek R12A and haven't been thrilled with the performance but I can't find anywhere to source the MO49.
Ironically, MO49 is made in the US but not available there. The one I got is US made and bottled in Mexico.
The next best thing would be the air duster route; at least you won't feel guilty if it leaks out :laugh:
gadget73
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Re: Photos of my A/C rebuild + timing cover reseal

Post by gadget73 »

Is the R437a meant to work better than the R134a then? I'm guessing since its primarily R134a, I could probably top up a 134a converted system with that and not have any horrible problems?

Whats the purpose of the foam in the rear of the compressor, a muffler or is that serving as a sort of oil catcher to help keep oil in the compressor rather than just everywhere in the system?
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

gadget73 wrote:Is the R437a meant to work better than the R134a then? I'm guessing since its primarily R134a, I could probably top up a 134a converted system with that and not have any horrible problems?
I don't think that would be effective. I believe the key is the HFC-152 making the blend behave more like R12. Plus, when charging from a large cylinder you are supposed to turn it upside down and extract liquid only, so as to keep the blend consistent.

As for the foam, I guess it's there for oil control. The compressor has an actual muffler bolted to the discharge port.
demetk
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Re: Photos of my A/C rebuild + timing cover reseal

Post by demetk »

Federico wrote:I don't think that would be effective. I believe the key is the HFC-152 making the blend behave more like R12.
Assuming you mean HFC-125.
Federico
Posts: 416
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: Photos of my A/C rebuild + timing cover reseal

Post by Federico »

demetk wrote:
Federico wrote:I don't think that would be effective. I believe the key is the HFC-152 making the blend behave more like R12.
Assuming you mean HFC-125.
:laugh: :laugh: :laugh:
Exactly!
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