Back in 2022, I fitted an upgraded A/C condenser to my 560SEC.   The A/C in that car wasn’t too bad, but the parallel flow condenser made all the difference.  From what I read, this is car more effective when using R134A.

The company that supplied the W126 condenser, Klima Design Works, have just released the 107 version.   This presented an opportunity to finally give the 450SLC the A/C that it deserves.  The kit comes with the upgraded condenser, plus the brackets and lines that you need.   You need to supply your own drier.

I supplied the kit to my mechanic to do the work.   From what I gather it was a bit more involved than the W126 install, probably because space is tighter on the 107.   During the install we found a hard line was missing.  While the line was possibly lost during customs inspection, Klima sent me another at no charge with very fast shipping, which I appreciated.   The kit bolted together well, the only slight issue we had was an existing A/C hose was a tiny bit short, and we had it remade.  Not sure if this was a RHD thing.

In any case, the difference is really noticeable.   While it wasn’t a very hot day when I picked the car up, I was quickly able to make the cabin too cold.   Even on not particularly hot days I was never able to do that.   I’m looking forward to trying it out on a really hot day.    So far I really like this upgrade.

While the new condenser is unpainted and the old one is black, once the bonnet is closed you could hardly tell.   I don’t want to paint it as it would probably loose some efficiency.  It is probably not an upgrade for a show car.  For a car like mine with 315,000km on the clock and used regularly, it is great.

While the car was in the workshop, it had all the bushes in the control arms replaced, and the front brakes done.  Some of the control arm bushes looked pretty bad, and the brake rotors had quite a lip on them.

I’m about to take the 450SLC on a 3,700km road trip.  This 450SLC A/C upgrade should really make a difference to how the car goes on that trip.   I’m also in the process of having the upgraded W126 condenser put on the 560SEL.

The post 450SLC A/C upgrade and front suspension rebuild appeared first on Classic Jalopy.

One of the first things I did was change the injectors.   The stutter when accelerating and hard starting when hot felt like a symptom of poor injectors.   I also didn’t want the situation of a leaky injector washing down my cylinder walls.   While not as cheap as the K Jet injectors, the MFI injectors are still available from Bosch and are not exorbitant.   The same cannot be said for the special ones used on the 6.3!  I didn’t do that job myself as it requires a special tool I do not have.     I had this job done at the same time as having the valves adjusted.

The next is a solenoid on the transmission that was impacting idle in gear.   The idle was too low even when adjusting with the idle air screw.    I’m not exactly sure what was wrong here, but it did fix my low idle problem.

The car also had a weak spark, so I had the coil and points changed.    When that was done, it was pretty apparent that the cap and rotor needed changing too, which is the part of the job I did myself.   This should have been so routine I would hardly need to mention it here, but there were a few things that I discovered along the way.

On the 80s cars, the distributor caps are marked with the cylinder numbers which makes installing them dead easy.   The older caps are not so marked.   This isn’t a problem if you’re just replacing the cap, as you simply hold it with the same orientation and move the leads over.   My problem was that in my haste I dropped the old cap and lost my orientation.   So much so that when I attempted to start the engine, it was extremely unhappy and didn’t start at all.  Obviously I had the order wrong.

This shouldn’t be a problem though.   If you can identify #1, you can start there and go around the cap with the firing order of the engine.   This is 1,5,3,6,2,4.   It wasn’t obviously apparent which one was #1.   In the end I discovered two ways of doing it.

The first is on the distributor there is a very fine line marked on the top of the outer rim where #1 should be.    You should be able to feel it with your fingernail.   From there, I noticed that the cap is actually marked.   There is a subtle raised section next to where the lead goes into #1.    In the photo below I have marked it with white paint.

The first time I did this, I just pulled on each lead to try and trace to each cylinder.   This is the lazy way to do it, as in the end I was wrong and the car still didn’t run.   Instead, I ended up doing it properly by taking off the leads and numbering each one, and also numbering the cap.    Perhaps overkill, but I ended up with a running engine this way.

The next step was to replace the plugs.   I had found these all fouled up on the 450SLC after I replaced those injectors.   They were even worse on the 250SE.    At least these plugs are much easier to swap out.  There are only six and access is very easy.

After replacing the plugs I took the car for a test drive.  It is a lot better.   Still not perfect but now all these components are fixed, it is probably worth having it tuned again.   It may also benefit from some good drives to clear everything out.    I’m planning on taking the car on a longer drive next week and will probably also take it on the next night drive.    At least for now, I seem to have no more M129 rough running.

The post M129 rough running appeared first on Classic Jalopy.

A quick test of the new coil had the car roaring back to life, so I swapped the new coil in properly.   This job can be done with the tools found in the Mercedes tool roll (screwdriver, 8mm and 10mm spanner), which helped as the car was not near my tools.

I also replaced my distributor cap and rotor while I was there, as the united fitted to the car looked rather worn out. Both ballast resistors seemed fine, so I left them alone.  I went with Bosch parts.    They have probably been on the car for years.

The end result is a car that starts more easily, has fixed some of the poor running and hesitation I was having with the car.   More importantly, it runs! At some point it might also make sense to replace the leads as they seem fine, but a bit old.

Total time was less than one hour and the car is transformed.   The last few months I had not been enjoying driving the car as much.   Now the car is back to normal it reminds me what a nice car do drive it is.   I should have realized something was amiss.

The post New coil, cap and rotor bring the SLC back to life appeared first on Classic Jalopy.