Throttle O-ring Replacement and More

On all of my cars while doing a leak test, I always find a leak around the throttle shaft (where cable hooks). After reviewing the message boards, people agree that it is the O-Rings. I have heard it is very hard to get this part. Please have all documents (Chiltons, Haynes or Manual) before removing the TPS and TB. Reinstalling it is Critical to the performance of your car.

Due to the danger of the throttle body sticking open while driving, DO AT YOUR OWN RISK! I will not be held responsible.

Andrew Bienhaus created a page with more details and another ring solution here. I suggest checking his site out as well. Having too many VFAQs is never a bad thing :)

Remove the throttle body from the car. Please consult manual on doing this. Click on http://www.plymouthlaser.com/tbody.htm to see some things involved in removing the body.

If you need to clean the Throttle body, it is best to do it now before disassembly. The reason is a lot of pieces need to be marked and you don't want to wash the marks away while apart.

Start by removing the TPS (throttle position sensor). If you do not plan to adjust, mark position with whiteout. I suggest adjusting it when you put it back together. It can make a big difference in shifting (did for me in the AT).

I show how to adjust the TPS here. Click Me.

Here is the throttle position sensor removed.

Once removed, mark how the arm that triggers the sensor is on. I used a CD marker to draw a reference line.

Use a 10mm socket and remove the nut. Keep the nut, washer and arm bracket in order.

Remove the 2 screws holding the throttle plate to the shaft. Be sure to use the correct size screwdriver or it will easily strip the screw head.

I know because....

Mine did. I used the smallest screw extractor (#1) in the kit (click here to see kit I use)with the corresponding bit (5/64). I did this because I had an extra throttle body with two good screws to reuse. Also, the extra shaft.

I drilled in dead center (avoid hitting the threads in the shaft) and inserted the extractor.

Another picture of extractor.

If you do not have the parts, back off until you have them handy. I did another throttle body and the 2 screws came right out w/o stripping.

Screw Out.
Remove the throttle plate and scribe a reference line on it to be certain it goes back the same way.
Take white out and make a straight line across the spring. This will help in reinstall.

Mark the position of the cable lever with a marker.

Use a 12mm socket to remove the nut.
Remove the spring (carefully, it will spin off) and place it all in order.
Mark the shaft position with marker or whiteout and slide it out through either side.
With a screwdriver, gently pry out the O-ring metal casing (holder). Note how it was in there (the metal side is up). Repeat on the other side. These are what hold the O-rings that seal the shaft.
Here is the casing. Scrape out the remaining rubber (what's left) with a screwdriver or knife.

Here is the replacement O-ring It costs about 20 cents to a dollar from Sears or Hardware store. You need.

1/2 X 3/8 X 1/16

#7 O-RING

STK NO 35724B

DANCO COMPANY
Place the new rings into the casing. The right one in Pic is in the casing.
I used this grease for the O-ring I heard this is what to use but not 100% certain. Silicone grease is recommended.
Greased up. This is important for 2 reasons. You need the shaft to rotate properly (No Sticking open at WOT) and helps seal the air in.
Use a 10 MM socket to lightly tap the O-ring and casing back in as it was taken out.
Here is a picture of it pressed in.
Do the other side the same way and slide the shaft slowly back through.

Place the throttle plate back in first. Once in close the plate as seen in pic (this will properly line the plate up inside the body) and place the 2 screws back in. You may want to use loctite to make sure they stay in (falling out into engine not good). Tighten screws. Check to see that it opens and closes w/o sticking.

Put the TPS side back together, and tighten snug (DO NOT OVERTIGHTEN) The nut strips easily.

Put the springs back on as they came off. Take a screwdriver and spin the inner and outer spring until your line in back lined up.

Take your time and rewind the spring. It will snap back and cut you. (I know).

Add the cable assembly arm and connect the two springs to it.

It is important the spring assembly works correctly!

Open and close the throttle several times and make sure plate does not stick, if it does stick DO NOT INSTALL IT back onto the car! I put the wrong o-rings in one and it was sluggish on snapping closed. Needless to say I did not install it and got the correct rings.
Put the TPS back on. Once again check the shaft and plate movement. Snapping your car into neutral while plate is stuck open on the road is no fun.

While the body is off, it is a good time to change these 2 coolant hoses that run to the bottom of the TB. They become weak after time and leak coolant.

I have already changed the one closest to the intake.
Here is the new hose on the car. The hose size is 3/8". I bought about 3 feet to do both hoses. I also used the Worm Gear hose clamps rather than the stock clamps. These can be tightened with a flat head screwdriver or 8 MM socket. Careful not to tighten too much as they will cut into the hose. I also added the insulation back around the hose and wrapped electrical tape around it. This protects it from sharp and hot objects.

I performed a leak test directly to the Throttle body and found zero leaks after doing this. This is a leak tester connected to the UIC pipe. I used 15 PSI.

That is all.

 

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