Last week, I talked you through measuring the inside of the nose on my E24 6 Series shark to determine the biggest condenser that will fit. I offered my rules of thumb: For any car, if you measure the inside width of the nose and subtract five inches, that gives you the width of the condenser that will fit comfortably once you take the hoses and their fittings into account; and if you instead subtract four inches, that gives you a larger, more aggressive condenser that should still fit, but may give you very little clearance to mount the hoses.

Perhaps I should added that, obviously, you need to take into account the fact that the nose width is probably not an exact number of inches, so you need to adjust accordingly. In my case, the fact that the width wasn’t exactly 24 inches but was a bit under was one of the factors driving me toward a conservative nineteen-inch condenser instead of a more aggressive twenty-inch unit.

I ended last week’s piece by saying that the nineteen -inch condenser had arrived, I had test-fit it in the nose, and there appeared to be plenty of room for the hose fittings. I wondered if I should step up an inch in width, but decided to delay that decision until I actually had mounting brackets in my possession, since once a condenser is mounted, there’s often not as much clearance as you initially thought.

Dealing with the condenser mounting brackets for a universal condenser is the part of the a/c installation process that takes up way more time than you think it should.

If you’re using a drop-in replacement instead, you’d have it installed in 90 seconds, but this is what you need to do to fit a modern parallel-flow condenser in a vintage car. I’ve done six of these—three 2002s, my E3, my E9, and now the E24—and in each one, mounting the condenser has had its own set of challenges and required its own unique solutions. You’d think it’s trivial, but in all likelihood you’ll be test-fitting everything a dozen times before you finally snug it down for the long haul.

All of these universal condensers have rows of regularly-spaced holes down the sides, and usually across the tops and bottoms as well. The first problem is that the hole spacing is not standardized; on many of them, the side hole spacing is ½", but on the one I bought, it’s 5/8". Vintage Air and other companies sell Erector Set-like universal mounting brackets (boy, does that description date me, huh?) with ½" hole spacing, but I have yet to find a set of these brackets with 5/8" hole spacing. Even the redoubtable McMaster-Carr, whose website is widely regarded to be the best organized in the world (go ahead; go to and type in “brackets”) doesn’t sort their brackets by hole spacing. To make matters worse, the hole spacing along the tops and bottoms of the condenser is usually different from the sides. Go figure.

But even if you had brackets with hole spacing that matched the condenser perfectly, they might not be enough, because the next problem is that you need to look carefully in the nose of your car and determine exactly which surfaces you’re going to mount the condenser to. If there are vertical surfaces behind and parallel to the condenser on both sides, then it’s pretty easy. You slide the condenser all the way to the right to create clearance for the hose fittings on the left, mount the right side on stand-offs directly attached to the brackets on the side of the condenser, and mount the left side on stand-offs, either with or without the Erector Set-like brackets, depending on whether the available mounting surface is directly behind the condenser or offset to the left. (To be clear, “left” and “right” are as you’re looking at the condenser through nose, so yes, I’m violating the “left is driver’s side and right is passenger side” convention.)

Below, I show the recent condenser retrofit in my E9 that I wrote about a few months ago, and the use of hard standoffs on the right and a bracket combined with hard standoffs on the left. The first two pictures show the stand-offs on the right side; they’re taken from inside the engine compartment, so in the photo they’re on the left (sorry). The first picture shows the additional complication that, on the E9, there was an obstruction at the bottom of the inside of the nose that the condenser needed to clear, requiring longer stand-offs than would otherwise be needed.

The third photo, also taken from inside the nose, shows the Erector Set-like bracket being employed to take up the gap between the left side of the condenser and the stand-off mounted to the nose’s sheet metal. But overall, this is a relatively simple condenser-mounting configuration.

Wait: Did you say mounted on the nose’s sheet metal? Exactly how are those stand-offs mounted?

Ah. You need to—just a minute, let me get my pit helmet and running shoes on—drill holes. (The Hack Mechanic now cowers beneath his E24, waiting for the jeering crowds to disperse).

Now, there are two schools of thought on this. One is that, on a car like the subject Euro ’79 635CSi with 220,000 miles and a non-original engine and transmission, who cares, really, about a few holes drilled in the nose? But on cars like E9s and mint tii's, you really need to present a lawyer’s case to drill any holes anywhere in the body.

When I updated the condenser in my E9 to a modern parallel-flow condenser, I took advantage of the fact that, nineteen years ago, I drilled holes in the nose of the car and used stand-offs to mount the condenser, so I felt entitled to re-use the same holes for mounting the new condenser—but felt honor-bound not to drill any more of them (re-using an old sin makes it okay). Thus, even though the E9’s new condenser was of a different size, with a different hole spacing on its side brackets, the mounting holes in the nose of the car were fixed points. The result satisfied my “no new holes” requirement, but it wasn’t pretty.

Back to the shark. Normally, what you’d do is procure or make mounting brackets whose hole spacing is the same as that of the side brackets, test-fit the condenser, put it as far right as it’ll go, split the difference between any space at the top and bottom, mark the holes you need to drill on the right, drill them, test-mount the right side, test-fit the brackets on the left, mark the holes you need to drill on the left, drill them, then mount everything for real. It sounds pretty straightforward, right?

The question of whether you should drill holes notwithstanding, there’s also the question of whether you can drill them. Sometimes the places you’d like to drill the holes are occluded by other sheet metal, and you can’t get a drill in there. Sometimes you need one of those right-angle drills to get it done. Sometimes you need to drill the holes from the back (the radiator side). This is a less-precise method, as when you slide in the condenser and brackets, test-fit it, and mark the holes, you have to mark them from the front, not the back. I’ll admit that I’ve eyeballed where the holes should go, drilled them from the back, and futzed with the brackets to get things to line up. It’s not something I’d do again.

If there isn’t a vertical mounting surface that’s parallel to the plane of the condenser, and the only available mounting surface on one or both sides is at a right angle to the condenser, it’s even more complicated. You need to procure, or make, right-angle brackets, and do a fair amount of measuring and cutting.

I sussed all this out on the shark. On the right side of the nose, there is no vertical surface directly behind the condenser’s side brackets, only one at 90 degrees to it, so I needed to buy or make some sort of right-angle bracket. At the bottom of the right side, there is already a small bracket that supports one side of the oil cooler. Initially I thought, great, I can drill holes in a bracket and slide it right over those existing bolts, but the nuts on the oil-cooler bracket are captured, meaning I’d need to get a new bracket behind the existing one, not on top of it. I decided it was more trouble than it’s worth.

I did make a mental note that the bottom of the condenser needed to be in either front of or behind the protruding bolts for the oil-cooler bracket. Eventually I got tired of that corner of the condenser snagging on those two bolts during test-fitting, and used the Dremel tool to cut a few inches off the bottom off the bracket on that side of the condenser so that it wouldn’t keep interfering.

On the left side of the E24’s nose, there is a narrow vertical mounting surface behind the condenser, but because the condenser must be slid all the way to the right to gain clearance for the hose fittings on the left, the surface isn’t directly behind it; it’s offset. So I’d need some combination of standoffs and universal brackets.

However, since I couldn’t find any brackets, flat or angle, that had a 5/8" hole spacing like the side brackets of the condenser, I figured that I’d just order 1.5"-wide flat and angle aluminum from Mcmaster-Carr and make my own brackets, cutting it all to length and drilling mounting holes exactly where I needed them.

Makes sense, right?

Unfortunately, I don’t own a bandsaw. I cut aluminum by clamping it in a vise, drawing a line on it, and using a jigsaw or a Dremel tool with a cutting wheel. Both are okay for trimming a short length off something, but neither is a great method for making long, precise cuts. I cut two pieces of angle aluminum and didn’t like the way they looked.

I ran down to Home Depot to see what they had for brackets. Hack Mechanic or not, I do have my limits; I bristle at the idea of anything that cries out, “I am a generic bracket for a tiny little shelf” being used to secure a condenser; and, aesthetics aside, most of the brackets they have at Home Depot are too narrow for this application (for rigidity, you really want something that’ll go through at least two of the holes on the side of the condenser). However, I was able to find some 1.5" right-angle brackets as well as flat brackets. Obviously, they didn’t have 5/8" hole spacing, but they did give me some pieces I could play with to see what the mounting issues would be.

I looked in the nose again and noticed that on both of the right-angled surfaces flanking the condenser, there were already two holes, halfway down, one inch apart. They were for the brackets that held the car’s original non-functional auxiliary cooling fan. I’m replacing that fan with a lighter fan for both the condenser and auxiliary cooling of the radiator (more on that next week). I thought that I might be able to use those existing holes and their mounting surfaces to hold the condenser, freeing me from having to drill any holes.

Normally I’d attach the condenser with brackets at all four corners, but I thought that if I used very beefy brackets in the middle of each side, and also supported the condenser at the top as well, it would be plenty secure. I noted that there was already a row of holes in the top of the nose over where the condenser would go. Plus, as I said, it would be challenging to attach a bracket at the lower right, because that’s where the oil cooler was attached. Even though this wasn’t one where a no-drill approach was strictly necessary, I became attracted to the idea of test-driving a no-drill approach so that I could use it elsewhere.

I could still make brackets from the aluminum stock I’d bought at McMaster, but since I was now using the existing holes that were at a right angle to both sides, and since the condenser needed to be slid all the way to the right to get hose clearance on the left, that created a big gap on the left that would require a home-made right-angle bracket bolted to a home-made straight piece of aluminum. A combination of both the kludgey mechanical and questionable aesthetic nature of this approach gave me pause.

So, back to McMaster. I found some very sturdy-looking right-angle corner brackets where the long side was 3.5" (part number 15275A66). A measurement showed that this was long enough to use on the left side, and would offset the condenser nearly flush with the right side. I’d need to trim the bracket on the right side to length. I ordered some smaller lighter brackets with elongated oval holes (15275A51 and 15275A53) to use to hang the condenser from the top.

When the brackets arrived, I first test-fit one needed for the left side of the condenser. I knew that all the holes in the bracket wouldn’t line up perfectly with the 5/8" holes on the side of the condenser, but in addition, I found that I needed to grind about an eighth of an inch off the end of the bracket to get even one hole to line up.

I then installed the left-side bracket, test-fitted the condenser, marked where I needed to drill holes in the bracket to align with the 5/8" holes on the sides of the condenser, took it all back out, drilled what I needed to in the brackets (not in the car), put it all back in, test-fitted it again, and carefully measured how much I’d need to cut the right bracket to accommodate the fixed 3.5" length (minus a little grinding) of the left bracket. I cut it and drilled some elongated holes 5/8" apart, test-fitted the brackets on both sides, and verified that I could indeed get the hose fittings on and off the left side of the condenser.

All that was left was to secure the condenser at the top. This was less to bear any real weight than to just make sure the condenser couldn’t somehow rotate about the two attachment points on the side. (By the way, you don’t really want the top of these universal condensers to bear a lot of weight anyway, as the bracket material is typically thinner along the top and bottom edges than it is on the sides).

Unfortunately, the small brackets I’d bought for the top were just a skoshe too short. And in addition, when I looked carefully, I found that the section of the nose above the condenser was angled slightly, so right-angle brackets wouldn’t work. I came very close to drilling holes and mounting extra right-angle brackets in the upper corners instead.

Then I looked at the right-angle brackets that I’d bought at Home Depot. I’d already mangled one during some test-fitting, so I only had one left. I gave it a few gentle taps with a sledge to increase its angle, then test-fit at the top of the condenser. Repeating this process a few times got the angle to the point where the bracket was flush with both the condenser and the underside of the nose. By chance, the bracket was the right length, and I could even use its existing holes and simply mark new holes to drill in the bracket at the top of the condenser.

But I only had one bracket.

Sometimes you remember things that people have said to you that made a lot of sense. My friend Lindsey Brown, shop foreman at the Little Foreign Car Garage in Waltham, once said to me, “At the shop, we have a saying: Put the goddamn part in the goddamn car!”

I cut the bracket in half length-wise with the Dremel tool. Voilà! Two brackets!

I test-fit both brackets at the top of the condenser, and used them to mark new hole locations to drill in the condenser’s top bracket, then test-fit all brackets with bolts in them.

Finally, I inspected the condenser from the back and made sure that nothing was protruding into the radiator’s space. Test-fitting the radiator itself is five minutes well spent.

So the bracket fabrication and test-fitting is done. The next step is to install the fan, and then put Nyloc nuts or lock washers on everything and install the brackets and condenser permanently. In truth, you need to deal with the fan in parallel with the condenser installation because most of the time you mount the fan on the condenser, and thus need to verify that, when you mark any holes to drill for any brackets, the fan doesn’t hit anything, but because this series divides up nicely into a condenser-installation piece and a fan-installation piece, we’ll cover the fan in next week’s installment.

But the main thing in these condenser installations is that you’re comfortable that the condenser is secure, and that you’re not going to look at it in a month and go, “Jeez, what a bloody kludge.” For me, this one passes those tests.

Next week: The fan.—Rob Siegel

Rob’s new book, Ran When Parked: How I Resurrected a Decade-Dead 1972 BMW 2002tii and Road-Tripped it a Thousand Miles Back Home, and How You Can, Too, is now available on Amazon. Or you can order personally inscribed copies through Rob’s website: