I thought I would do a guide for dismantling a 16v throttle body (I had promised I would). I have missed a couple of the dimensions out by accident (mainly on the first stage), so be aware. Also, I have tried to describe the components as best I can, but I have included pictures as a backup. My advice is to take plenty of pictures as you go along - I have included what I think to be the most useful ones here, but its better to be safe than sorry. Also, make sure you measure the distance of the grub screws when you take them out - that way it should work the same as before! Usual disclaimers apply - i.e.. not my fault if you balls it up. How to Dismantle a 16V KR Throttle Body 1. Remove throttle body butterfly screws (for both butterfly's) - these are shot peened from behind, so can be quite tough to remove. The larger of the screws correspond to the smaller butterfly (for when rebuilding). The stamped numbers and screw heads face towards the engine. Note that the smaller butterfly is notched on one edge. 2. Undo 13 mm bolt on large butterfly shaft - on the underside of the throttle body. Remove small serrated washer. Unclip spring from washer with catch on (note that the washer has a notch for the spring) - remove washer. Remove plastic top bush. Untension spring and remove. Remove thin washer (didn't get the dimensions - apologies!) Remove plastic bush (inverse of previous bush - like an upside down hat) 3. Now, working from the top of the main (smaller) butterfly. Remove nut (14 mm) Remove serrated washer (16 mm o/d) Remove second serrated washer (20.5 mm o/d) Remove plain thin washer (12 mm i/d, 20 mm o/d, 0.5 mm thick) Take tension of the spring and remove accelerator cable arm - note the there is a sleeve in the middle of this - it may or may not come out with the arm - its dimensions are i/d 9.8 mm, o/d 12 mm, depth 10.7 mm. Image of spring end locations. Remove spring - upward facing hook goes over accelerator cable arm, the other end goes over the next bracket on the mechanism. Remove thin washer (i/d 12 mm, o/d 19.6 mm, 0.5 mm thick) For the next step, I wedged the throttle in what would be the open position to allow for the removal of the next piece of the mechanism. Release the tension on the small spring which is hooked onto the next piece of the mechanism (large butterfly - note that there is a notch of the spring). Remove the large butterfly spindle - should just pull out - it pushes through some roller bearings at the top and bottom of the throttle body housing. Note - there is a small washer at the top of the spindle - on the two I have dismantled, it did not fall out, but it is there. Its dimensions are o/d 15.4 mm i/d 8 mm and 0.5 mm thick. Remove plastic bush (top). Remove metal sleeve (o/d 12 mm, depth 4.9 mm) Remove thin washer (o/d 17.8 mm, i/d 10 mm, think this is 0.5 mm thick) Remove thicker washer (o/d 17.8 mm, i/d 10 mm, 1mm thick) Remove bottom plastic bush (inverse of previous one). 4. Spin over the throttle body housing. Remove the smaller butterfly spindle. You can remove the now empty throttle body for the time being. Careful not to lose any parts! Remove washer (o/d 17.8 mm, i/d 10 mm) Remove plastic bush - note that the previous washer sits inside this. Remove spring (hooked end is down) Remove washer (o/d 17.8 mm, i/d 10 mm, 0.16 mm thick) Remove plastic bush - inverse of previous one. Unhook bottom spring from next part of the mechanism. Remove bracket with plastic bush - bush end toward the bottom of the mechanism. Unhook the bottom spring. Hooked end towards bottom of the mechanism. Remove plastic bush. 5. Done! Rebuild in reverse order - use your pictures to help locate the springs - its actually not as bad as you think to get them tensioned in the right position - this is where your pictures come in. Note that some of the pieces of the mechanism have been stamped to make sure they grip the spindles - they will come off, they just need a little lubrication and a bit of a wiggle! MOST IMPORTANT THING - When you get to step 2 on the rebuild - DO NOT TIGHTEN THE SHAFT BOLTS UNTIL THE BUTTERFLYS ARE BACK IN! I did, and twisted the shaft, as there is no strength in them due to the slot through the middle. With the butterfly's back in, you can nip them up (not too tight) and they will be fine. I hope this helps somebody - there isn't much on the net about stripping these - its actually not too bad as long as you are methodical. Here's how mine turned out in the end.
I dismantled my 16V throttle body because there is an air leak from around the butterfly shaft and I can tell you that above how-to misses some critical infomation. If you looke very closely you will see that the needle bearings hide a very small rubber shaft seal. It's easy to miss it, especially because on the top side of the throttle body, the shaft seal hides on the inside of the bearing where you can't see it. But it's there. On the bottom bearing, the seal is on the outer side. See my picture: Now, where to get these
Thanks, I will have a look. Original part is INA F-95776. It's a needle bearing with incorporated seal into the outer race.Never seen this before.
I've tried to measure it and identify it on the INA web catalog. Looks to be this one with inner seal on one side (yellow marked on picture). https://ibb.co/T12pT9R It wouldn't surprise me that many people have this leak but might've never found out! I've also noticed the butterfly plates are not sealing the throttle body throat when closed. You can see clear gaps. This is a common defect and could be solved by coating it with Molykote 321. Very special dry film lubricant.
Is there such a thing as a rebuild kit for these? When you put the screws back in the butterfly did you secure them in any way. I believe they are deformed at one end to keep them in place?