[Witek_M]

Those are steel thread forming bolts. If they are breaking just below the head they are stuck in water pump hole.

 

[260e crusier]

Just got a box from FCP today. Mahle fan clutch is Made in China. Lemfoerder motor mounts Made in China. Lemfoerder transmission mount Made in India. Sigh. I was also disappointed in FCP packaging. They literally threw my parts into a box without padding and shipped them. That included transmission and brake fluids which somehow did not leak.

Same thing happened to me one time. Brake fluid cans were all dented and boxes for other parts broken open. Amazing air filter survived.

 

[MBGraham]

Those are steel thread forming bolts. If they are breaking just below the head they are stuck in water pump hole.

You are right, they are steel. I should have gone and checked before typing. They broke so easily, I assumed aluminum!

I will of course buy new ones. So they formed the threads in the timing cover! There is a bracket top left. Pump has holes, but no threads. So I guess same bolts could be used without first tapping the holes?

Anyway, I first installed the new pressure port seal then finally got the pump off! 75% success rate with the bolts (or 25% failure, depending on how you look at it ) 2 steps ahead and x number backward

Some pictures:

Broken bolt locations

Bolt with missing head, plus view of inner pump casing (no wear!)

Broken bolt 2 (sorry a bit fuzzy)

Broken bolts 3 & 4

One bolt should be easy. Two hopefully not too bad and the one that is broken off flush will take some work!

 

[Witek_M]

I tap those two holes for bracket M6x1 on the bench. Unless I install MB rebuilt pump where threads are formed already.

Only holes that are tapped during M112/M113 production are head bolts and crank bearing caps. Everything else is thread forming bolts. Self tapping.

In earlier engines using rubber gasket for water pump corrosion sets in from outside.

 

[Deplore]

For that one stud that's sticking out, use something like this

Amazon.com

Others will need to be tapped and drilled in very carefully.

 

[MBGraham]

For that one stud that's sticking out, use something like this....

Others will need to be tapped and drilled in very carefully.

I have been sitting thinking about what I have or can get locally to get those bolts out.
For the long one, I am thinking of just double nutting it and seeing if it will release now after sitting overnight with penetrating fluid. I will also try some heat on the aluminum.
For the short ones, I will first make a drilling guide. Then try left handed drilling for a start. If they don't come out, then try extractor. Both after penetrating oil and some heat.
Not fun, but at least access is good.
I will replace all 6mm bolts. Probably only available from dealer, but will check. 8mm probably still OK. Had no problem removing them. But may get those too.

 

[Deplore]

Double nut is risky. It may work, but puts all the stress on one focal point on the stud.

The tool grips the entire stud. But on other hand, the tool moves the stress point to the point where the thread enter into the body of the engine.

Heat and penetrate would be your friend here. Ideally a penetrating fluid that doesn't turn into a toxic gas that kills you when you heat it up....ala old brake cleaner or the DI cleaner from ACdelco. So yeah. Try not to die changing a water pump.

 

[Witek_M]

I have a friend that works in mining industry. For obvious reasons you can't light up a torch in coal mine.
What they use on stubborn fasteners is induction heaters.

Here is sample of one more on the scale of automotive use. I have not used one but I do like the concept.

 

[Witek_M]

View attachment 2813445

Using fine wire brush and sharp scribe try to remove as much corrosion at the base of the bolt. Right now corrosion seals thread entry and penetrant will not creep in. Kroil is choice of penetrant.

 

[MBGraham]

Well, I removed 3 of the 4 broken bolts this morning.

For the two with about 5mm sticking out, I used the Jeep guy's technique in the Youtube video I posted. Just hammered on a 3/16" socket. Cleaned off surface oil in area of bolts. Applied heat with propane torch (Small flame) for 2 minutes (it needed that long). Then removed with 1/4" ratchet.

For the longer stub, I used the double nut technique. Again needed 2 minutes of heat and stub came out.

The other one only sticks out a mm or two. Can't grip onto it. That will need Plan B (or C!). Visitor coming, so it will have to wait until tomorrow after I visit the stores.

 

[MBGraham]

Soon I will need to order a new set of bolts. Questions that came to mind:

• if MB bolts are used, are their replacements also self threading bolts as , I think Witek mentioned the originals were.
• if not MB, choices could be hex heads instead of Torx . And stainless vs steel. Preferences?
• Are the steel MB bolts coated?
• Should some type of thread coating be used?

Separate subject. It looked like the rubber o-ring seal had sealant on it. Some sort of yellow gunk on seal and in slot. Never been off before, so this is original. Is some type sealant recommended?

 

[Witek_M]

If M8 bolts came out with normal force reuse them. Order new M6. All those bolts are coated with Dacromet. It gives them bluish appearance that some folks mistake for blue thread locker.

Yellow gunk is residue from coolant dye. I fill seal groove with silicone grease to keep seal in place. You will have to maneuver new pump into oil cooler hose and behind temp sensor clip from bottom up. Need to make sure seal does not get dislodged in the process.

 

[MBGraham]

If M8 bolts came out with normal force reuse them. Order new M6. All those bolts are coated with Dacromet. It gives them bluish appearance that some folks mistake for blue thread locker.

Yellow gunk is residue from coolant dye. I fill seal groove with silicone grease to keep seal in place. You will have to maneuver new pump into oil cooler hose and behind temp sensor clip from bottom up. Need to make sure seal does not get dislodged in the process.

Thanks - I hope I get to that step soon

 

[MBGraham]

The 10 M6 bolts came to C$60 at the dealer!

4th bolt still not out. Drilled centre of bolt without a problem. Bolt wouldn't budge using easy out, heat & penetrating fluid and it eventually slipped. Decided to increase hole size to get better grip. Bad move. The tip broke just as I started the drill. It left a small piece in the hole. I need to get that out. Then drill old bolt out and re-tap. Should probably have done that in first place. M6 kind of small for extractors.

 

[MBGraham]

Got at that broken bolt today.

Decided to drill and tap the bolt hole rather than try again to extract. But first, I had to get by the part where the drill tip had chipped off and embedded itself.

I used the old pump as a drilling guide with copper/brass sleeves in the hole being repaired.

• First, I used a 3/16" diamond hole saw to drill out about 1/4" of the stub of the old bolt. (That is where the drill tip chip was). That worked quite well, albeit a bit slow going.
• Next, I decided to drill out the bolt using the drill bit size for an M6 tap (13/64"). I had about 4 of these bits, but none of them would make much of an impression on the bolt steel! I went out and bought a new cobalt bit at Home Depot. It had no trouble. I just had to be careful not to drill too deep!
• Was thinking of using a Helicoil, but decided to first try tapping the hole I had already drilled. I didn't have a bottom tap. So tapped first with a standard tap, then "modified" it by grinding off the end to turn it into a bottom tap

MB bolt now screws in and holds tight. A bit loose at outer end, so may put a little JB/Weld on bolt thread in that area.

Next step is to clean up the shop! And move on to installing! Also need to clean up inner casing flange face and the seal groove. Hopefully I will get this job done before long. Luckily, no rush

Deplore - This is post #94. Looks like you may win your bet.

 

[Deplore]

Looks like you may win your bet.

I'm just poking fun at BW in general. Been a trend I've noticed lately, threads with very technical issues are resolved even before the first page is done, whereas threads with basic ass stuff like misfires, changing tires, and yes, water pump, gets to multiple pages.

Still, that's good news that you're finally coming to the end!

 

[MBGraham]

Still, that's good news that you're finally coming to the end!

We are now at #96 . (But only 43 posts since #53 when I finally acquired a fan tool and could start on the job )

I would have been done with this a long time ago if I hadn't had to make the tool for the fan and the bolts hadn't broke. I couldn't have been more careful with those bolts, yet they still broke. I suspect I might have got a big bill if I had had a local shop do the work and they broke the bolts!

 

[Witek_M]

I have no problem with thread count.
I do admire precision and craftsmanship.
Mr @MBGraham deserves round of applause.

 

[MBGraham]

I'm just poking fun at BW in general. Been a trend I've noticed lately, threads with very technical issues are resolved even before the first page is done, whereas threads with basic ass stuff like misfires, changing tires, and yes, water pump, gets to multiple pages.

I admittedly have started a few long threads! Technical issues not always resolved. Living where I do, there is only one other DIY guy that I know who works on old MBs. And they are mostly 123 diesels (I also have one of those). These forums fill the gap.

This is a thread that went all over the map before I finally discovered the actual problem. It got to post #210 .
This one only got to #77 . (apparatus case blower)
This one only got to #53, but may have to be re-visited

#98 and counting.... I better go out and do some work.

 

[SocalSam]

I admittedly have started a few long threads! Technical issues not always resolved. Living where I do, there is only one other DIY guy that I know who works on old MBs. And they are mostly 123 diesels (I also have one of those). These forums fill the gap.

This is a thread that went all over the map before I finally discovered the actual problem. It got to post #210 .
This one only got to #77 . (apparatus case blower)
This one only got to #53, but may have to be re-visited

#98 and counting.... I better go out and do some work.

All good. Different styles.

If I can figure it out, it might get a single post in "What did you do..."