617 Water Pump Removal of broken hex bolts
 

Hello All,

My two 300CDs needed water pumps.

The red one, only broke one bolt, going back into the block. But with further inspection, I noticed that someone had already broken a bolt, and drilled about 1/2 a bolt diameter off, thats why it sheered the bolt.


My next 300CD water pump bearings are bad. I put on a housing/water pump from a junk yard since, 4 of the bolts broke right off, when I was trying to loosen them.

So, I have one housing that has 4 bolts stuck in it. One housing on the car with a bad waterpump (from the junk yard).

I need some pointers on getting this bad water pump off, without sheering off the bolts. I was using a 1/4 ratchet, and I broke the bolts. Im actually very careful, and I am an apprentice machinist, so I have a delicate touch. Just these bolts suck!

I am going to use penetrating oil to loosen them. Anyone have any other tricks? I think Im going to replace them with stainless steel bolts they are M6x1.00 x 18mm long!

Well thanks for reading, I tried a search too!

sorry
 

you are having trouble. penetrating oil patience time and heat may work. i cant remember ever breakning any myself but maybe i am lucky. if you reinstall with anti sieze you should be fine. because of the steel into al there is apparently some electralisis because i have removed these bolts before to find they are about half worn away.

on the broken bolt. take a center punch and mark the center firmly. then take a drill the same size a little smaller than the solid part of the threaded area and drill on through the length of the bolt and a little more. then tap it with the correct tap. with a little luck you should be back in business. be meticulous on the centering and on keeping your drill perpendicular to the block. take your time... it is worth the effort. too bad po botched it up for you.

good luck.

tom w

I recently pulled the water pump on the SD and none of the cap screws gave any troubles, thankfully.

But, I also removed the water pump housing to clean it up a bit and replace the rusted fasteners. It's five hex head cap screws that are slightly larger than the screws for the water pump. When you remove the housing, you can easily deal with any broken screws from the pump. Of course, I'm assuming that the housing screws will come out without a problem.

You will need a new gasket for the housing. It's a little gasket that only seals the water passage. When you go to purchase it, you'll swear that they are giving you the wrong gasket. Most of the housing sits directly on the block, without a gasket behind it. Very strange design.

I would strongly advise against the use of stainless fasteners. The material is considerably softer than a hardened steel fastener and it is almost a certainty that you will round the head when attempting to remove. It's much better to use anti-seize on the threads of carbon steel fasteners.

Use a small torch and heat ONLY the remaining part of the bolt. Heat then allow to cool. Be very careful. Do this several times. The expansion/contraction will usually loosen it up.
Use wax on the stubborn bolt while its still hot. It will pull the wax into the thread when it cools.
Again, be very careful with the torch with all that grease, leaking diesel.

Use plenty of anti-sieze when re-installing.

Always worked for me. Only burned one to the ground. :eek:

If you don't have a good fire extinguisher. Do NOT attempt this!

judicious use of brut force!

Hit the heads with a ball-peen hammer. A few whacks seems to break loose the bolts. Works like a charm or you can get good at drilling bolts out=)

Put new bolts back with the new WP.

Mike

on a w115 diesel all but 2 of the water pump bolts snapped. just very
corruded. lots of white aluminum
i took off the housing, filled the two open holes with epoxy, rotated the new
water pump and drilled & tapped all new holes.
it worked. yuck

don

Great Ideas, Thanks.

I talked to an MB mechanic, and he said that these bolts breaking is common, but not super common. He said, that since Ive had such bad luck with the other two housings, maybe this third one will work out for me.

Thanks, Ill try these things.

Ive got 2 sets of new bolts, and 2 sets of new gaskets for the W/P and housing.

I know this stuff gets burried in the Diesel section, but does anyone else have any ideas for me?

I will be attemting this work sometime this week.