1991 318is M42 Refresh Journey

[Digitalwave]

I'm in love with this car. Excellent work! Keep it up.

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Current AC System Set-Up

It’s 100% stock and original. So, as of today, 35 years old. Never messed with it. It is R-12. The AC shop added some R-12 about 5 years ago and changed out the resistor at the condensor fan.

Overall, it runs good now but not always comfortable. The fan/blower speed works. It runs around 60-65 degrees during summer time. Colder (50-60f degrees) during winter/fall/spring. I just want a cooler system during Texas summer months to make it more comfortable. Sitting in traffic in 100 degree is no fun when the air starts warming up.

To start things off,

1. I wanted to see what the state was on the AC system. So, I took it to a reputable AC shop here this week and they discovered my compressor is leaking.

2. Got some quotes for windshield and window tinting. Front wouldn’t be tinted but rather ceramic coat for heat shield. Figure this would help reject heat as much as possible to keep the cabin cooler.

Things I’m considering….

- Convert to R-134. Just want it easier to maintain for future
- Complete new AC system including hoses, minus the evaporator
- Window Tints/Ceramic Coat Film

What I’m learning is that you can’t buy a new OE or OEM compressor anymore for M42. Hearing and reading reman are not reliable and some kits from AC Solution but not a full kit. So, I have to figure out how to source all these new parts from multiple sources. I’m okay with AC system not being OE or OEM at this point but do want a OE/OEM look. I may look at getting custom hoses made.

Example of current temp:

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For next thing to tackle, I’m thinking about the AC system after I get to enjoy the E30 for few months.

Figure the AC project might take little more time to research, source and execute.

So, if anyone has any experience or wisdom on this topic, please chime in.

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Test Drive Update

Alright. Been driving it for about a month with everything done, including alignment and all the work done performs well.

Steering Rack: The new (to me) steering rack is great! No more bus-like loose feel. It’s tight and more responsive. I feel the road more with it. Much nicer on the freeway. Don’t do any tracking or hard driving so turn to turn ratio is not a major factor for me even though the new set up is shorter.

Front Suspension: It’s definitely tighter and I can tell from past to now. Simple things like going over the speed bumps is noticeable and nicer. No bouncy reaction. From height standpoint, I will get the actual measurement, but the front valance is a tad lower than an 2025 BRZ/GR86 (did a comparison but forgot the measurements). There’s a little front rake (front lower than back). I like this stance. I will get the rear suspension refreshed at some point to get it fully complete.

Front Brakes: Maybe little better. Previous set up fine. It has new rotors, brake pads, fluid, pistons, hoses, so just glad that’s been refresh.

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Took it to the alignment shop and got it all aligned. Here's how it looks now from underneath the car...

Here's the driver side:




Here's the passenger side:



Got the plastic protective engine cover back on. I also cleaned up the plastic cover as it was baked on with cosmoline.

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Here's the rotors and pads. I've had the new EBC pads and Zimmermann rotors that I've been waiting to install at some point. Was waiting for the previous to wear down but never got to that point until now. I also ordered new brake lines. I ended up going with OEM rubber lines. Been thinking about stainless steel versions but since I'm keeping everything pretty stock with engine, etc. figured OEM is perfectly fine. Did a full brake fluid flush since the reservoir was drained while doing this project as well.

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Here's how it looks after being rebuilt by PMB Performance. It comes fully assembled ready to go.

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FRONT BRAKE CALIPERS

I got the original front calipers rebuilt by PMB Performance. When I did the math of reordering new parts (sliders, rubbers, etc), media blast and zinc plating, it just made sense to send it off and get it rebuilt.

Below shows how it looked in original state. After 35 years, nothing was going to come off from just washing and brushing it. Media blasting was the only way.

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For me, I assembled the shock, coil springs, etc. on a bench and then installed the new dust shield, bearing, brakes, etc on the vehicle. I ended up torquing the wheel bearings while the car was on stands. Didn't have to lower it with tires on it. Used dremel to cut the nut to locked it. Below is the high level sequence.

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FRONT STRUTS (REFRESHED)

Got all the parts in and tackled it this weekend and got it complete.

I did have to borrow a coil spring compressor from nearby auto store with the shorter Koni''s shock to get everything installed. When disassembling, since it had OEM Bilstein shock, there was no tension.

I also got a tip from a fellow forum member about installing and ordered a new E30 Top Hat Washers (Part #31306763966) vs. using E30 Top Hat Washers since I was using a E90 Top Hat.



Used Koni provided plastic bump stop, top washer (OE version does not fit), locking washer and nut.

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I couldn't find any measurements at all for the 1210's against OE (at least with Bilstein B4) set-up. So, here's my measurement comparisons. Hope this is helpful for those looking for it.

Total Length (fully extended):
Bilstein B4: 24"
Koni 1210: 21 1/2"

Shock Body
Bilstein B4: 17.0"
Koni 1210: 16 7/8"
- basically the same body length. What's interesting is the E30 Strut is 16 7/8".

Shock Shaft Fully Extended (not what to call it)
Bilstein B4: 7.0"
Koni 1210: 4 1/2"
- Koni is 2.5" shorter than Bilstein B4

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FRONT SHOCKS (KONI 1210 SPORTS)

Wanted to share the front shocks I ended up choosing, the differences and why...

When doing my research today (circa 2026) on the internet, reddits, facebooks, forums, etc., many found Bilstein B8's to be little stiffer than Koni's. Not 100% if this is true. This was just nice to know. I ended up going with Koni's for few reasons...
1. Koni's were on sale ($200/ea vs. $250/ea).
2, Koni's are adjustable. This is a nice feature.
3. Appears the front Koni's are easy to adjust from the top.

I found 3 yellow front Koni versions that fit E30. This was little confusing but I think I found the differences:

1210: Shorter for lowered springs (mainly used on E30 M3s)
1021: Longer/extended length (mainly for E30 coupe and sedans)
2277: Used for E30 convertibles

I went with 1210's. Between H&R springs, E90 Top Hats, etc., I figured I needed something shorter than normal. Couple forums posting was happy with this set up on their E30's (non-M3). Previous owner had the Bilstein B4 (OE replacement version) with the H&R springs and E90 Top Hats, so I was able to compare the two. Just FYI, when I was dismantling the current set up, I didn't have to compress the springs. I think this is because the B4 had longer shaft with shorter springs.

Box Label:



What comes in the box:

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Here’s how it looked before washing it up…I thought it was completely surface rusted. It ended up being brake dust snd dirt.




Here's how it turned out after media blast and new powder coated. Good as new. Ceramic coated it as well to make it easier to keep it cleaner moving forward...at least for little awhile.

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FRONT DUST SHIELDS

Just waiting for some final parts to come in. I was going to get new brake dust shields. At this time of writing, new OE shields are little over $100 each. But after getting it soaped/washed and scrubbed away decades of brake dust/road grimes, decided to just refresh the OE ones. Getting it sand blasted and powered coated. It’s in great shape. Minor surface rust in small area.

Here’s how it looks right now (before refresh) after soap washing it up. It has cosmoline on some area. It’s the white/yellow stuff on the paint. Cosmoline are so hard to take off.

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uturn, thank you for the reco! Didn't know that one. Current set up looks like e30. I think the shop the previous owner used over 10 years ago hodgepodged it. I was missing a small washer on one strut. Trying to document everything that's going into the struts for future reference as many small parts do have part numbers on it. Thanks again.