hi,

I am replacing the coolant pump, and I am stuck with a t40 that wouldn't budge. It is slipping very bad. So is the case with the T30 that is holding the coolant inlet -yellow circle. I tried pb-blast and tried twisting the screw with hammering with screwdriver. No luck. Any one have any experience with removing difficult screws?

[img alt="The red circle is the t40 holding the pump and the yellow circle is the t30 holding the inlet pipe. Both are slipping.
"]https://cimg8.ibsrv.net/gimg/www.mbworld.org-vbulletin/2000x1504/img_7870_d1ada22a9e888b60187160919cc255d765197e74. jpg[/img]
The red circle is the t40 holding the pump and the yellow circle is the t30 holding the inlet pipe. Both are slipping.

 

There are 3 types of torx :
There are three main types of internal Torx screw heads: Torx, Torx Plus, and Torx ttap.
Torx is the standard, six-pointed star shape.
Torx Plus has a rounder profile for increased contact area and higher torque transmission.

Confirm that you torx tool is the standard one.

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Thank you for your response. Yes, I have a standard torx which I use to remove the other bolts for the thermostat and around the coolant pump. One t40 and one t35 is slipping. I assume the screw head lost the grip during the previous pump replacement and they don't bother to replace the bolt.

 

ohh no, the head is so low profile it is no fun to undo a "bald/slipping" one.
Many location you can't acces with vice gip.

They are either 8 millimeters M8 ( T40) or 6 millimeters M6 (T30 ) thread diameter.
Just becareful when and if you want to use welding . It may damage your electronic modules if you don't do proper disconnecting of certain wires and/or connectors and battery.

See if this can help you

Good luck man....

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You have a lot of options here in terms of amount of work, chance of success, and likelihood of damaging other stuff in the process. They all suck, but you need to do it...

Grabbing the entire head with a vice grip will often work, but sometimes not.

If you have access, you can dremel a slot in the head and hammer a flat-head screwdriver into the slot, then turn the screwdriver with a box wrench. Make sure you get a really good and wide slot so you can use a screwdriver head that spans as much of the head as possible, preferably all of it. Make the slot tight so that there is absolutely no slop on the head. It's better to make it slightly too narrow and pound the screw driver all the way in.

This may be very difficult or impossible with the amount of space you have.

Screw extractors very hit or miss. They typically don't work well with bolts that strip because they are corroded in place or stuck for some reason. You also need access to hammer them in as well, so if you can't hammer in a slotted screwdriver, you probably can't hammer in a screw extractor.

I have had both of these methods work and both of them fail.

See if you can get a vice grip on the head first. Try to get it as tight as you possibly can and still get it to lock. Use a tool to clamp them down if you need to (bigger pliers). Use vice grips with a curved jaw profile for the most grip.

Heat/cool cycles and penetrating oil can help if it is stuck, but again, it's probably not stuck. The head was probably buggered during install, or you may have slipped out a few times trying to get it.

I can't see the image you attached to see how bad your situation really is. It is possible to get out but it may take several tries with different approaches to get it.

I don't envy you, but I have been there.

Good luck.

 

DIYMAN, can you repost your photo?

 

Many thanks to everyone for being so helpful. The T30 (yellow circled) and T40 (red circled) finally gave in today. I have attached the images.

Since both the T30 and T40 were slipping, I had to remove the inlet to get better access to the T40. I used my grinding tool to cut a slot into the T30’s head, then used a screwdriver and hammer to drive it out through the notch—you can see the final screw head! Once the T30 and the inlet were out, I finally had room to work on the T40. This time, the bolt extractor fit perfectly onto the T40 head and I was able to break it loose without issue.

 

For those that have never seen one, look up a manual impact driver. As long as you don’t go crazy with the hammer, this is the way. I meant to type this the other day. Glad you got it sorted.

 

Nice work. PITA, but you still came out way ahead $$ compared to having a shop do the work.

 

thanks for the suggestion. I will add the manual impact screwdriver to my tool kit

 

Awesome. I knew you'd get it.