123 Water Pump Fitting

[stiffy]

Hello,

After much consternation (moreover, a number of sad exchanges with dodgey mechanics, with delusions of retiring on the proceeds of doing this job) - I have decided to roll up the sleeves and change a water pump.

The car is a 116 '75 280s - but is mechanically similar to the 123 (thanks for the person who pointed that out).

Can anyone tell me if there any 'surprises' involved in replacing the pump?
Is it something you could do with an ordinary set of tools and reasonable patience?

It looks pretty straightforward - but I am intrigued after the last quote suggested that it would be a $300 (labour only) undertaking.

[300SDog]

Right you are, its an easy job......

1) Get rid of the radiator/fan shroud. Many backyard mechanics trash the shroud entirely because it gets in the way of maintaining the engine, doing coolant flushes, checking belts, ignition timing, etc.

2) Slack the alternator belt and remove it from the waterpump pulley....

3) Unbolt the fan and remove the pulley too...

4) Then you swap the water pump, maybe having to rap the old pump with rubber hammer to loosen it.

Old timer's trick is to rub little bit of oil into the new water pump gasket to assure tight seal without hassling with gasket sealer glue. Toughest thing about doing this job on my 240D last June was lining up the bolts that attach the fan and pulley to the new water pump. Clean all parts and surfaces thoroughly, work meticulously slow and it will take you less than 2 hours.

[stiffy]

Thanks DieselDog - I'll let you know how I fare.

Maybe I'll start up a garage specifically focussing on replacing water pumps on mercs and make my fortune - $150 p/hr = more than a gynaecologist and not as messy.

I found that removing the radiator improved access no end. It's not hard to do just takes extra time. However, this was on a W123 where there may have been less space.

[stiffy]

I had some great experiences with the radiator - and am now a dab hand at getting it out and back in (i think about ten minutes is all it takes).

1. Looking for a replacement radiator at a wrecker - guy brings out a 110 radiator - the oil cooler is on the opposite side. I point this out - he tells me it's normal - it will fit! (I have driven 2hrs through dense suburbia to get it)...

Of course it didn't fit...but it was only when I tried to install it that I found that out. I quickly reclaimed the old leaking one from the garbage and put it back in.

2. I take the car to radiator guy to have it bronze welded. He tells me that he can fix it for $100 if I take it out myself. No problems I say - I take it out, and carry it 5kms to him - by foot. He looks at it again and tells me he will need to re-core it as well - add $400.

I put it back in again.

Finally got one that fitted.

Now my $%#ing water pump needs replacing...

Ha.

[ctaylor738]

It is a simple job if the bolts don't break, which they frequently do. Patience, penetrating oil, and some tapping.

I would leave the shroud in. It is there to force the fan to pull air through the radiator at idle and low speeds, so it does help cooling.

[dmorrison]

Yes, as was saaid, leave the fan shroud installed. You will have an easier time doing the job if you remove the radiator. If you choose not to remove the radiator I would suggest puting a piece of cardboard over the radiator so you don't accidentally damage it while tring to remove the water pump.

Then when finished, head down to Harry's Cafe De Wheels and have a Tiger for me. The family and I visited your wonderful
Country a couple of years ago and loved Harry's, Sidney, Melbourne and Canberra.

Dave

[stiffy]

Looks like Harry's will have to wait...

I am stuck - need help...

After wrestling with various parts of the car and clearing a reasonable work area (removing radiator, alternator - as it refused to budge, removing fan, hub and belt), I finally commenced the task of removing the pump.

Now - the last bolt (right at the bottom of the pump) is concealed behind the harmonic balancer - I cannot see any way of accessing it without removing the balancer - which is something I do not have the tools to do.

Re-reading the posts above, and noting the reference to the ease in which the replacement task should be - I am wondering whether we are talking about the same thing.

Is there a mounting behind the actual pump that attaches to the block - and if so, is this what I should be taking off first, then replacing the pump on the housing and attaching it to the block?

AFAIK, the bolt behind the harmonic balancer holds the water pump housing. If you are changing the pump then there shouldn't be a need to remove the balancer.

[stiffy]

There is no way of getting the pump off without removing that bolt.

[stiffy]

Has anyone (who has actually performed this task) know how to get at the last bolt??

[stiffy]

Here is the replacement part:

[kerry]

I'm suspecting that at one place on the harmonic balancer, there is a cut-out that will permit access to the bolt????

[stiffy]

Here is the problem:

[stiffy]

Here is the motor:

*In reply to Kerry - I checked the balancer, there is no recess that allows access to the bolt ...