Tuesday, July 12, 2011

Air Pump Block off plate repair after broken bolt

OK, first off I will say: Don't try this at home! I am writing this for informational purposes only and am not suggesting anyone try this. I took a big chance trying this and with a lot of luck it came together and has worked for me. I can only hope that there will be no ill effects in the future from this.

So I previously removed the entire are pump system after it had failed. I followed this "how-to" for the removal process. It includes everything you need to know. As usual with my experience working on "older" cars, when I got to the last bolt (on the head of course) it snapped:

There was not enough of the stud left to get at with vise grips especially considering where this is located (back side of the motor). There also wasn't enough space to get a drill in there (possibly if the steering linkage came out). I had ordered my block off plate from KSTech before I started and got it within a few days. I considered just putting the plate on with the single bolt and using some gasket maker but I knew it was asking for problems sooner than later. After spending some time under the car inspecting the situation and the port itself I came to the conclusion that there was nothing immediately inside the hole that could be damaged. It really seems like it is a long (straw like) cavity. Being confident (or lucky?) enough with this theory I decided that I could plug the hole itself, so off to "Lowes Racing" for some supplies!

I chose this set of bits because it was what I could get all at once. Below is a pic of all the supplies I got (from top to bottom):

-KSTech block off plate w/ gasket
-3/8"-16NC tap
-3/8"-16 X 5/8" set screw (allen head)
-M8-1.25 X 16 Hex head bolt (new replacement for the bolt that did come out)
-Loctite thread locker (went with the removable just in case)
-Loctite RTV blue gasket maker

The block off plate was about $25 and I spent another $28 at Lowes for all the tid-bits (would have been about $15 without the Loctite products, see below).

I chose the tap size from a guess-timate I made while inspecting the hole as well as based on the available set screws. I don't think it could have worked any better! It was just the right size without having to drill the hole at all. This was the most difficult place I have ever had to use a tap. There is very little room to maneuver, and even less room to get any leverage. I took my time while tapping, backing out every time I had any forward advancement. This helped keep things clear as well as ejected most of the metal shavings. As stated before I really don't think they had anywhere to go in there but I can't be 100% without seeing a section view of the head. I also had to switch back and forth from above and below the car to get the leverage on the tap that I needed. I really beat the heck out of my hands and arms in this process that took the better part of an hour just to finish the tapping!

Once finished with the tapping (only enough to get the set screw in flush) I started the car before installing anything. I let it run for a short while with a couple revs to try and "clear" the passageway of any remaining metal shavings. Once satisfied with that I got back under and installed the set screw with the appropriate allen wrench, leaving it completely flush. It is very difficult to tell it is even in there in the bad cell phone picture but here it is installed:

This is what I bought the Loctite for although I have not put it on yet for two reasons. 1) It is probably overkill and 2) I wanted to make sure everything worked out before making it harder to get out.

Now all I had left was the KSTech block off plate w/gasket and the gasket maker. I am pretty sure this would be fine without even using the plate but since I paid the $25 for it I might as well use it and it will ensure that the set screw doesn't back out at all. I was going to use the gasket maker in between the block off plate parts but decided it was unnecessary. I bolted the plate and included gasket on with the new bolt on the one side that I could:

So far there are no leaks and the car is running good. I had already flashed a new version of the Cobb stage 1 map that I disabled the codes for the air pump and will be taking it out for a longer drive to make sure no issues come up.

I think my plan is; when the time comes to replace the clutch I will see about having the broken bolt drilled out if is more accessible. Again, at this point the plate isn't really doing much but I might as well so it can be on there correctly.

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