Replacement of injectors and air distribution pipes - k jet R107 500SL

[matthewz108]

Spent a couple hours on Saturday replacing the fuel injectors, seals, injector holders, and the air distribution pipes on my R107 500SL. This is just a write up for anyone who might want to attempt it in a similar way.
The car had a slight stumble at idle, and was difficult to start at times.
I checked the area by spraying brake cleaner in s few spots, and found some possible leaks.
The existing air distribution pipes were siliconed in places by the previous owner which looked like a cover up of leaks anyway, so I purchased the parts and got it done.
Steps involved were:
1. Disconnect battery
2. Clean area around injectors with degreaser and compressed air
3. Spray all fittings with wd40 or similar and have a beverage of choice
4. Disconnect the fuel line hoses at either the injector or the fuel distributor. I chose the injector end, as I just didn't want any possibility of anything getting into the FD. I used a 14mm crows foot to get a good purchase on the fitting, but a good 14mm open end spanner should do. I worked on one side - 4 injectors - at a time.
5. Disconnect the injector clamp bracket, using I think a 5 or 6mm Allen key
6. I then removed the air distribution rail complete with injectors, by wiggling out
7. Clean out the injector seating area once the injectors are removed and check that the injector holder o ring or other bits are removed.
8. Install in the reverse order, making sure to fit new o rings on the injector holders, and new seals on the injectors. Torque up fittings 10-12 Nm to injectors.
9. Re connect battery, check all connections, then start engine, checking for leaks.
10. Have celebratory beverage (or two) of choice.
Part numbers (that I used - vehicles and specific needs may vary) were:
8x Injector 0000785623
8x Injector seal 1160700077
8x Injector holder 1170700455
2x Air pipe 1160940982
1x air distribution pipe 1160900882
2x air pipe connectors 1179900578
4x air pipe end plugs 1169971286

A little fiddly, but a fairly simple job for those that are thinking of attempting it.
Car idles much smoother and starts easier now.
Now to jump into the vacuum system...

[Nabstud]

Good stuff!!

[brycedunn]

Good stuff, those old rubber bits looked really perished.

[matthewz108]

Yes, they were much worse than they appeared, as I'm sure it's always the case.
Some of the injectors were even siliconed into the holders. By the time you take them out, silicone them and pray they don't leak, you may as well change the seals. They are like $1 or something stupid, and the injector holders are about $5. The worst thing is that the previous work was done by a workshop engaged by the previous owner and not a home mechanic.
Not ground breaking mechanical work, but happy to keep this forum going.

[brycedunn]

Yes, they were much worse than they appeared, as I'm sure it's always the case.
Some of the injectors were even siliconed into the holders. By the time you take them out, silicone them and pray they don't leak, you may as well change the seals. They are like $1 or something stupid, and the injector holders are about $5. The worst thing is that the previous work was done by a workshop engaged by the previous owner and not a home mechanic.
Not ground breaking mechanical work, but happy to keep this forum going.

That is pretty shocking a professional did this. from the photos I assumed it was a home bodge by a previous owner.

[Christo C]

Not surprised; over the past 50 years I have had three car engines trashed by so-called professional mechanics in central Sydney … all people who should have known better

[matthewz108]

Yes, when you're 80 something years old and the mechanic charges you $700 for injectors, you'd think you're getting what you paid for. When I bought it, the old guy was just frustrated because it was costing him thousands every time he took it in, and it was never really sorted, I felt sorry for him. And they're such minor, simple things to do properly. There were wrong spark plugs, botched wiring, leaving cracked fuel hoses after replacing injectors...the list goes on. I get the shits when I see dishonest operators taking advantage of unknowing owners.

[der_panzer]

Todays's mechanics dont fault find the scan tool does it for them. so looking for vacuum leaks is a really foreign thing to them.