Look below for final conclusions.

Yes do let us know as I have a 90 model too.

i posted and ill let you guys knwo what he says. if not ill take a trip to the local hardware store and get a set of thick ass o rings. i knwo what the store has because i used to work there

By the way... here's the vfaq if you don't have it already...

http://www.plymouthlaser.com/tbor.htm

Turblown said:

By the way... here's the vfaq if you don't have it already...

http://www.plymouthlaser.com/tbor.htm

Click to expand...

ive taken em apart a few times.

this i swhy i wanted to knwo because im tweakin my n/t tb as we speak. i have the hump taken out and im polishing the inside and outside. just need to finish then ill post some pics

i just got done doing my 90tb this weekend... one side was a #7 style o-ring.... but the otherside was different... i cant remember what size it was, but i picked it up at the zone.... in anycase, my TB doesnt seem to want to shut all the way now... its a little tight.... so yea... i either need to mess with the adjustment., or my other thought was letting those o-rings warm up a few times.... and maybe they will fit better.... i used plenty of lube, but we shall see what happens....
(on a side note, can you do the FIAV elimin. with a 90 TB.... it has a different design than all the others... or do you just straight up remove/loop the coolant hoses and be done?)

The 90 TB's only have 2 seals like the 91-94's. The problem is that no one sells the direct whole seal like machv does for the 91-94's. I have owned two 1990 cars and after both TB's leaking and a few others I have finally swapped to a 92 TB. Its much easier because you can buy the whole seal w/metal ring inside from machv and its a snap. You can't do the faiv on the 90's because as I see it you can't open the TB's like the 91-94's. I have tried to change the seals on my 90 and it would still leak, sometimes even worse.
I would suggest getting a 91-94 TB, changing the seals, swap over the isc, rewire the TPS, and use that instead. Thats what I am currently doing.

eclipse90gsxt said:

Thats what I am currently doing.

Click to expand...

Hey man I sent you a PM cuz I couldn't get it to fit with the 91-'94 TPS. Post some pics if you can!

-Thanks
Wes

i just went to home depot and bought a bunch of o rings and stuck them in till i found one that worked and fit

hewhoisknot said:

i just went to home depot and bought a bunch of o rings and stuck them in till i found one that worked and fit

Click to expand...

So you just rebuilt the 1990 TB with new o-rings and it sealed without boost leaks? Very cool. Do you happen to know the sizes of the o-rings needed? Thanks.

-Wes

I did the o-ring thing with my tb and just used a few i had around the house. The important part is cleaning out the old metal piece very well before you put in the new o-rings. When I put it back together i used some silicone spray. Sealed fine and my tb moves better than before. DSMatMSU I had the same problem after I installed my tb with it not closing all the way. Turns out the button that tells the car that the tb is closed (I forget the name) just needed to be adjused.

Turblown said:

From what I've gathered it can be done with two #7 o-rings. But if you want to get them from a dealer, this place is cool. Just email the guy and he should be able to let you know what the part numbers are.

Click to expand...

there is no part number for the shaft seals. if you tell them that you're looking for throttle body shaft seals they'll probably look at you funny because they'll have no idea what you're talking about. the only thing they'll be able to do is sell/order you a whole new throttle body.

RamenPride said:

there is no part number for the shaft seals

Click to expand...

This is true. By the way if you have a 91'-94' Throttle body you can find the complete seals at www.machv.com , but the dealership won't have them for any year. I'm actually in the middle of a rebuilding the 90 TB I have, so I will update this post with the appropriate o-ring sizes and maybe some pics!

-Wes

Turblown said:

This is true. By the way if you have a 91'-94' Throttle body you can find the complete seals at www.machv.com , but the dealership won't have them for any year. I'm actually in the middle of a rebuilding the 90 TB I have, so I will update this post with the appropriate o-ring sizes and maybe some pics!

-Wes

Click to expand...

Mach V wont have them till mid august according to web site. i used #7 o-rings and they fit perfectly. no leaks!

Okay here are my conclusions on this subject.

After putting it off for a while decided to find and fix some boost leaks this past week. All leaks were coming from the TB area so I decided to test it directly at the TB.



I added pressure to the system and sprayed windex on the TB and found severe leaks at the BISS and near the TPS (shaft area).



I had done my research and felt the easiest way to fix the problem was to just replace the TB with a 91-94 TB... so I got one off Dsmtrader.com. I had read that the 90 TB was smaller (intake diameter) than the 91-94 TB and that the 90 TB was difficult to rebuild. Well after purchasing the 91-94 TB I have found that they are pretty much the same size (intake diameter), and they will not fit on a 1990 DSM.



From this point I decided to rebuild the 1990 TB using the VFAQ found here even though those instructions are for rebuilding a 91-94 TB. There are only slight differences in the rebuild.



When I pulled the shaft out and took it apart I laid out all the pieces. I found that the original o-rings were very frail and actually fused with the metal rings around them.



I scraped at the metal rings for a while, but the old o-rings would not come out. I ended up having to torch the metal rings until the old o-rings were red hot. I then scraped out the metal rings until I could see silver. Finally I cleaned them off with some carb cleaner.



From here I proceded to get some new o-rings. I believe I got them at Autozone. Here's what you need to look for... at least these worked for me.

larger o-ring = 1/2" outer diameter, 1/16" thickness
smaller o-ring = 7/16 outer diameter, 1/16" thickness

I followed the VFAQ to the tee including the plummer's lube. Did the same for my BISS. I put gasket sealer on the TB and TB elbow gaskets just as a precaution. And I also had to reposition my TPS in accordance with the Hayne's manual.

So far this has fixed the leaks in the TB and given me back some boost.

Hope this helps.

-Wes

That was a great post. Thanks for taking the time, Wes. Would you mind submitting it as a tech article? I'm hoping Ludachris will add it since you've got some useful tips there that apply to testing/rebuilding throttle boddies for all years.

Just used this thread to rebuild my 90. I just used my gas stove and held the ring in the flame. Works great will cook the seal and just crumbles right out of the ring.

Turblown said:

Okay here are my conclusions on this subject.

After putting it off for a while decided to find and fix some boost leaks this past week. All leaks were coming from the TB area so I decided to test it directly at the TB.

I added pressure to the system and sprayed windex on the TB and found severe leaks at the BISS and near the TPS (shaft area).


I had done my research and felt the easiest way to fix the problem was to just replace the TB with a 91-94 TB... so I got one off Dsmtrader.com. I had read that the 90 TB was smaller (intake diameter) than the 91-94 TB and that the 90 TB was difficult to rebuild. Well after purchasing the 91-94 TB I have found that they are pretty much the same size (intake diameter), and they will not fit on a 1990 DSM.

From this point I decided to rebuild the 1990 TB using the VFAQ found here even though those instructions are for rebuilding a 91-94 TB. There are only slight differences in the rebuild.

When I pulled the shaft out and took it apart I laid out all the pieces. I found that the original o-rings were very frail and actually fused with the metal rings around them.

I scraped at the metal rings for a while, but the old o-rings would not come out. I ended up having to torch the metal rings until the old o-rings were red hot. I then scraped out the metal rings until I could see silver. Finally I cleaned them off with some carb cleaner.

From here I proceded to get some new o-rings. I believe I got them at Autozone. Here's what you need to look for... at least these worked for me.

larger o-ring = 1/2" outer diameter, 1/16" thickness
smaller o-ring = 7/16 outer diameter, 1/16" thickness

I followed the VFAQ to the tee including the plummer's lube. Did the same for my BISS. I put gasket sealer on the TB and TB elbow gaskets just as a precaution. And I also had to reposition my TPS in accordance with the Hayne's manual.

So far this has fixed the leaks in the TB and given me back some boost.

Hope this helps.

-Wes

Click to expand...

I'm gonna use this

Just to add, the 1990 Throttle Body uses the Chicago Rawhide CR 3930 seal on the spring-side and the smaller CR 3030 seal on the TPS side.

Full specs:
3030 CR 8x12x3 HM4 R
3930 CR 10x14x3 HM4 R

Also note that the 1990 inner TB gasket is different from all other model years

I had to bring this back. Where can I order those rawhide seals? I don't care if I have to buy them in bulk, that stupid TB shaft is my only boost leak and it needs to go.

Funny that this thread just came back up. Yesterday I finished rebuilding a 90 TB. I got the seals at Motion Industries. They are listed as oil seals. Then give them the part number. They couldn't find it with JUST the number (which is retarded). Don't bother with the scrapping the metal ring out. The new seal doesn't use them. You just need to reuse the plastic washer, the metal washer (NOT the one with the rubber inside it), and the metal C-clip. Thats it.

Also you have to grind the tip off the TB plate screws, and apply ALOT ALOT ALOT of force down into the screw when taking them out, others wise you'll jus strip them. DO NOT resuse the screws, GET NEW ONES. the screws are 4mmx10mm screws. You can get them at Home Depot, in little plastic baggs. They are made by Crown Bolt Inc. marked

MACHINE SCREWS
FLAT - PHILLPS
4mm X 10 MM

I can't describe it any better then that.

Use Loctite and smash it with a punch on the other side a couple times after you screw them all the way through. That way you are 100% that they will never work them selves out and get sucked into the engine.

ha i was just looking all day yesterday for those dam screws finally found them at home depot same ones in hardware.

Turblown said:

By the way... here's the vfaq if you don't have it already...

http://www.plymouthlaser.com/tbor.htm

Click to expand...

For those of you looking for this dead link here it is curiosity of the WayBack Machine


http://web.archive.org/web/20140214011939/http://www.plymouthlaser.com/tbor.htm