So REALLY how easy is it to replace the injectors? - PeachParts Mercedes-Benz Forum

300sdToronto · #1 09-26-2007, 10:25 AM

So I have read all of the pictorials on several sites which describe replacement of the injectors as an "easy" do it yourself job. However my injectors look original and there is no evidence or any marks to suggest they have been replaced.

Certainly my experience with working on old cars and tractors is that so called easy jobs can suddenly turn into a nightmare when the part in question refuses to budge.

The job itself looks quite straightforward
- get everything really clean
- label and remove the fuel lines
- replace each injector and crush washer one by one
- probably do the glow plugs at the same time as they will be accessible

However I've read in here about the chamber into which the injectors are mounted coming undone, rather than the injector ... and crush washers which refuse to come out of the hole. And glow plugs that snap off......

How easy is this job with a basic metric socket set (I have a set of deep sockets) and a set of ratchet wrenches for the glow plus?

vstech · #2 09-26-2007, 10:34 AM

use PB Blaster... and let it soak for a few days if your injectors look dry and rusty...
also when you get the 27mm/1-1/16" Deep socket on the injector body really well, HIT the wrench, DO NOT JUST PULL WITH EVEN PRESSURE!!! you must use sudden force. those PC rings will stick to the injectors, and the tool is pricey to put them back.

oldiesel · #3 09-26-2007, 02:03 PM

If you are maintaining all the old farm equipment that you list i really dont think changing injectors is going to be much of a challenge for you.Follow vstech`s advice after cleaning away all the rust and dirt that you can,and once the injectors loosen a 1/2 turn clean again and blow things clean with compressed air if its available,if not a shop vac can help to avoid as much as possible any dirt/rust dropping into your engine. My $.02 Don

kartoffelpanzer · #4 09-26-2007, 02:18 PM

Not a big deal to replace the injectors, it was one of the first things I did on mine.

I remember there being some issue with the glow plugs, if I recall correctly the Haynes manual gives a pretty high torque when installing the new plugs. My mechanic told me not to tighten them this much. I don't remember what I torqued them to but it wasn't to the Haynes spec; in the end everything seems to be working fine.

toomany MBZ · #5 09-26-2007, 02:28 PM

FSM mentions 55 lt. lbs.

300SDog · #6 09-26-2007, 04:02 PM

Tinfoil wrap injector pump openings when you detach the pipes - ONE grain of sand will raise hell if it falls in ther. Deffinitely soak all fittings with PB plaster overnight before the operation. I like keepin a gallon bucket of kerosene around for chuckin and scrubbin parts and fiddly bit nuts'n bolts. And brass brush "toothbrush" size you gotta have for scrubbing threads. Hell, a round rat-tail file sized one will probly be your most valuable tool. Gun cleaning brass or steel brushes in .45 calibre are your best bet. Thats how you free up crush washers petrified in place.

As usual with DIY operations, work excruciatingly slow and thats okay. And tackle sideline stuff along the way like vac connexions and fiddly bits that need attention. Retorquing misc nuts'n bolts bleedin a little oil and whatnot. Meanwhile if injector swap takes all afternoon thats good.

300sdToronto · #7 09-27-2007, 09:40 AM

Quote:

Originally Posted by DieselDog

Tinfoil wrap injector pump openings when you detach the pipes - ONE grain of sand will raise hell if it falls in ther. Deffinitely soak all fittings with PB plaster overnight before the operation. I like keepin a gallon bucket of kerosene around for chuckin and scrubbin parts and fiddly bit nuts'n bolts. And brass brush "toothbrush" size you gotta have for scrubbing threads. Hell, a round rat-tail file sized one will probly be your most valuable tool. Gun cleaning brass or steel brushes in .45 calibre are your best bet. Thats how you free up crush washers petrified in place.

As usual with DIY operations, work excruciatingly slow and thats okay. And tackle sideline stuff along the way like vac connexions and fiddly bits that need attention. Retorquing misc nuts'n bolts bleedin a little oil and whatnot. Meanwhile if injector swap takes all afternoon thats good.

Thanks for all this advice. I must say I am most concerned about getting the crush washers out cleanly and easily without any crud falling into the cylinder. I expected the injectors would need some prep to allow them to come out easily. I'll keep you guys posted. I can't get the parts until my next visit to Sunnyvale in mid Oct, when I will get them from Phil (injectors are about $110 each here in Toronto vs about $50 from Phil).

vstech · #8 09-27-2007, 10:05 AM

don't worry about crud getting into the cylinders. just clean the crap out, and spin the motor over with the injectors out before you reassemble everything!