Mil.Spec throttle body shaft seals don't fit

[BigTyla]

I ordered the Mil.Spec seals from Aby at the Evo forums. I'm not sure how others are able to get these to fit, but I completely ruined a set of these seals trying to put them on my 1G turbo throttle body. The metal ring protrudes out too far making it impossible for them to properly fit. I used a 10mm socket to attempt to gently tap them in but they never came close to fitting. Am I missing something? It turns out I had one new seal like the ones that come from Chicago Rawhide. It was lying in a box of parts that came with the car. It fits perfectly, so I have reason to believe it's not just me.

Sucks that I just peed $18 down the drain. Just ordered a set from ExtremePSI. Just thought I should let you guys know that I do not recommend these seals.

 

[Detective Coating]

What throttle body are you putting them in? You need to make sure they go in perfectly straight. Yes they are really tight and i've ruined them before not having them straight but have rebuilt tons of tb's using the milspec seals.

 

[BigTyla]

It's a '91 throttle body, so not a '90 which I know it will not fit. I had them as straight as possible and did not try blindly forcing them in. I simply used a 10mm socket on an extention and lightly tapped with my rubber mallet. When I could tell it wasn't working, I tried multiple times to realign the seal to no avail.

Honestly, the Chicago Rawhide seal I had lying around fit perfectly with no need to tap on it. It went in with very little finger pressure, which is how I would expect a properly-sized seal to fit. I would recommend this type of seal instead.

 

[BoostedBeaver]

Maybe Snowborder will jump in here and give his opinion. He even sales a kit with these Milspec seals. Personally, I purchased a set of Chicago Rawhide seals because someone had them local for 10bucks and I had a boost leak. Would like to hear how these seals fit for others.

Robert

 

[snowborder714]

The issue with the Mil.Spec seals is the inner edge is not chamfered, which is why they don't go in smoothly. I installed a set in a customer's N/T throttle body (yes, they do work on these with a bit of creativity) and ruined one in the process. As Justin said, they need to go in perfectly straight. I used a screwdriver to push mine in. The handle had a flat top, which was good to drive the seals in. The blade of the screwdriver helps center the screwdriver in the seal/shaft holes, and you need to tap it in ever so slightly and slowly to make sure you get it going in straight. I wouldn't recommend using a hammer to tap them in, as once you start going in crooked, it just gets bad really quickly. I used a combination of pushing and a rubber mallet.

I have since made a tool to help drive in seals based on Aby's drawing. I'm looking forward to using in on the Mil.Spec seals to see how much easier it makes the process.

 

[BigTyla]

The issue with the Mil.Spec seals is the inner edge is not chamfered, which is why they don't go in smoothly.

This was exactly my thought in retrospect. Chamfer the inner edge inward slightly and I bet it would have been much easier.

 

[GSLENK]

I installed these... I had to be really careful, 1) because I only had one set. 2) It was my first TB rebuild.

I did it "similar" to how I do races in hubs. (well not really but I applied the technique).

I used plenty of Dielectric grease. I used a flat piece of soft wood (any wood should do) and a mallet. got it flush, then I used a long socket that matched it perfectly to push them the rest of the way in.

IIRC I had to put one seal in, the TB shaft, then the last seal. and carefully because the first time I tried to snug it all together I popped the first seal out by shoving the second one in somehow.

All I know is, they work fine for me. At least for a BLT of up to 30 psi.

 

[snowborder714]

IIRC I had to put one seal in, the TB shaft, then the last seal. and carefully because the first time I tried to snug it all together I popped the first seal out by shoving the second one in somehow.

It was probably by fully seating the shaft that you popped out the spring-side seal. The way I got around this way to install 2nd seal, seat the shaft fully (which popped out the 2nd seal slightly), and stack up a bunch of washers and then put on the shaft nut to tighten them down. This smoothly and evenly pushed the spring-side seal back in place to stay.

And yes, lots of dielectric grease is good.

 

[cabot2g]

Has anyone tried freezing the bushing and heating the TB?

You can cool and heat tight tolerance parts to make them easier to insert.

 

[snowborder714]

Sounds like too much work

I've only installed one set of Mil.Spec seals, so I'm unsure how the seal would react to being cooled/frozen. And I'd be afraid of heat ruining the nice media blast finish I put on the throttle body (if using a torch).

 

[cabot2g]

Bushing goes in the freezer, TB in the oven. The oven set to 150-175 wont do anything to the metal. Just make sure its just a stripped down TB.

 

[snowborder714]

Possibly would work. I'll consider it if my tool doesn't work.

 

[BigTyla]

Fitment aside, Aby is a good person to deal with. We've been trading emails back and forth for the past couple of days on the issue, passing out measurements to each other and such. I measured my seals to be 18/32" and the bore I was trying to fit them in as 17/32" (I did not have my caliper handy). This seems a tad inconsistent with Aby's measurements, but his measurements showed the seal to be 0.01" larger than an Evo throttle body he had lying around. I tend to trust the accuracy of a caliper more, but regardless, the seals just don't work for me. He asked if I wanted a refund and I replied that I would only request a partial refund, to which he agreed. That was very nice of him!

 

[snowborder714]

Aby has been very helpful to me as well, even sending me a replacement seal free of charge (along with an additional order I placed) since I bent/damaged the one. I had ordered only 2 seals and couldn't finish up the N/T throttle body, mentioned I damaged one, but wanted to purchase more, and was only charged for 4 when I was sent 5. Very nice and helpful person to deal with.

 

[snowborder714]

I have since made a tool to help drive in seals based on Aby's drawing. I'm looking forward to using in on the Mil.Spec seals to see how much easier it makes the process.

This tool made the install extremely easy. If for some reason you plan on installing more than a few sets if mil.spec seals, I'd highly recommend having the tool made. I didn't even have to worry about the seal going in crooked or catching an edge, but instead pushed it straight in with ease.

 

[liquidsilver]

This tool made the install extremely easy. If for some reason you plan on installing more than a few sets if mil.spec seals, I'd highly recommend having the tool made. I didn't even have to worry about the seal going in crooked or catching an edge, but instead pushed it straight in with ease.

Sweet!

I would recommend the tool even if installing a single set. If BigTyla's measurments are correct it would make perfect sense...or even moreso that there may be a metric vs. standard issue. I'm not the best at what I do but I completely destroyed mine upon install and took every precaution other putting my tb in the oven. I think it's like tightening an allen bolt...can't do it without a hex.

 

[TexasTurbo]

I'm sorry please remind me what's wrong with the OEM seals. I don't recall Mitsubishi ever going out of their way to get "mil-spec" seals. That sounds like something cool to sell to those evo guys.

 

[Boomdeeze]

I'm sorry please remind me what's wrong with the OEM seals. I don't recall Mitsubishi ever going out of their way to get "mil-spec" seals. That sounds like something cool to sell to those evo guys.

I got one installed by snowbarder into my evo 3 TB, the reason is I want a seal that I know can handle the boost. Its a great investment.

 

[snowborder714]

Well, first of all, they don't sell OEM seals. The "normal seals" (as I call them) are the ones that MachV and ExtremePSI sell, which is just a seal without any metal case. I know they have been tested up to 30 - 35 psi via a boost leak test, but I'm not sure how far they're able to be pushed. If you want the extra security and plan on running 40+ psi, the mil.spec seals will give you that without questioning.

 

[TexasTurbo]

Hmmm, so you're saying that the "standard" throttle body shaft seals cannot be obtained via a Mitsubishi p/n and that they don't include a metal portion for strength in the seal? Very interesting. Is there a link where I can go look at these?

 

[biglady112]

Granted I live in a big city, but all of our local seal and bearing suppliers always have these in stock. And they have always had themetal ring in them. We have bought over a dozen sets through the past few years. Just give them the metric sizes you need and they should be able to get them if not already in stock. We have had good luck with both 90 and 91+ throttle bodies. No need to buy something like this online unless you live in the middle of nowhere. You just might be surprised at what kind of resources you have locally to put a car together.

 

[snowborder714]

Hmmm, so you're saying that the "standard" throttle body shaft seals cannot be obtained via a Mitsubishi p/n and that they don't include a metal portion for strength in the seal? Very interesting. Is there a link where I can go look at these?

There's absolutely no Mitsubishi part number for shaft seals that I have ever found.

Here are the 3 seals I have on hand. I've used the normal shaft seal the most and the mil.spec only on request. I have yet to try the metal cased seal, but will hopefully be having a friend test all 3 seals (those being the only variable).

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[92AWDHX40]

I'm working on installing the milspec ones now I'm gonna try the method Brian used.