1982 300SD Water Pump Leaking

[johntksr]

Can anyone point me to a DIY for replacement of the water pump? What parts will I need? etc. I have searched for a DIY post, but have not found anything specific enough. I am a noob but feel I can probably tackle this job.

John

[toomany MBZ]

Pretty straight forward. I changed one out on my '82 300D. I used a 10mm box end wrench, that was ground down rather thin, (otherwise you don't have room to turn the wrench to remove the four bolts to get to the pulley that Hans built, do da, do da) anyway, the four bolts closest to the engine. There is a cross over pipe you need to remove, it'll be obvious, I used a bit of sealant to hold gasket in place, be careful when torquing the pump to 24 ft. lbs. I don't think I even removed the shroud, just work around it, and the hoses. I ordered my pump from here http://*************** or you can click on buy parts at top of page, being sure to obtain gasket, some pumps come with it.

[tangofox007]

It's an easy job. (At least if you don't have any complications like rusted/broken bolts.) The toughest part is removing the fan bolts. If you use an open-ended wrench, you will likely round them off. A good-quality box-end wrench usually won't fit unless it is ground to a thinner dimension.

It's a good time to replace your belts if they need it.

[TheDon]

I used a regular 10mm wrench and it fit fine.


steps

drain coolant

1: remove fan shroud and let it hang
2: remove fan clutch with fan still attached (Careful do not round the bolts)
3: with fan and clutch removed loosen the belts to the water pump by releasing tension on the altenator
4: unbolt the pulley that is on the pump

5: spray some PB or w/e you fancy onto the bolts for the fun of it and remove the water pump

6: clean gasket area and re install.....

7: reinstall all of the other stuff.. getting the pulley and belts on can be a pain since starting the bolts to the pullet on the water pump with the belts on it requires the same skill as opening and closing the fuse box

add coolant


buy a new pump.. not a reman...

[tangofox007]

Originally Posted by toomany MBZ

There is a cross over pipe you need to remove, it'll be obvious

There is no need to remove the pump housing nor the crossover line if only the pump is being replaced.

[pjc]

Since you'll be draining the coolant to do this job, now would be a good time for a thorough cleaning and citrus flush, and replacement of the old coolant with Zerex G5 (gold container) if you haven't done it recently. Search for threads on cooling system flush, and bleeding. Time consuming, but not difficult. Good luck.

[tangofox007]

Originally Posted by TheDon

4: unbolt the pulley that is on the pump

The pulley is retained by the same bolts as the fan.

Originally Posted by TheDon

buy a new pump.. not a reman...

I will take a genuine MB reman over a new pump from McParts any day.

[toomany MBZ]

Originally Posted by tangofox007

There is no need to remove the pump housing nor the crossover line if only the pump is being replaced.

Good, one less thing to worry about, that came from the Haynes manual, have forgotten if I did/needed to remove, easy in and out.

[blindwolf]

You might want to go ahead and pull the radiator first. It will give you a lot more room to work and you don't have to worry about punching a hole in it. It is real easy to do. If you don't remove the radiator, then place a thin board or thick piece of cardboard in front of it.

[johntksr]

Thanks everyone for your comments...I took a look at the fan bolts last night, and do need to ground my 10mm box end wrench. I have completed that job on a bench grinder at work. I ordered a new pump and required gaskets yesterday. I will also replace the belts as required.

What (citrus) product is used for the radiator flush?

Wish me luck,

John

[vstech]

citric acid powder approx 2.2 lbs of it. dissolved in hot water then flushed in the system... for a week... after degreasing the block/water passages with tide dissolved in hot water first... tons of threads on the subject.

[johntksr]

I followed step 1 through 5 without a problem...however the pump doesn't seem to want to seperate from the housing? any tips?

[tangofox007]

Tap it with a hammer. Sometimes they need to be broken loose.

(This assumes the the water pump bolts have been removed; step 5 failed to mention that requirement.)

[johntksr]

Thanks! That did the trick!

[johntksr]

I just finished putting in the water pump tonight...UPS delivered it at 6:00 and I had everything done by 8:00. The hardest part was removing all the old gasket material. Thank you everbody for your help. The engine temp's are much cooler....and no more leak...

John