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T Roof Panel Gasket Replacement

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This turned into a bit of a mis adventure which seems to be a disturbing theme associated with a lot of my recent maintenance forays.

The driver side weather strip on the roof panel had a bit of a tear in it where the roof panel rests on the A pillar. It has been there as long as I have owned the car and I expect it occurred from somebody letting the panel drop into place when putting the panel back on the car. The rubber on the gasket is backed by a metal insert and the gasket is rather thin at this point so if you hit it with something hard it would be fairly easy to tear.

IMGP4158.JPG

In retrospect, since nothing was missing from the gasket (no torn out chunk) I should have just sealed it up with some urethane; but, since the gasket was 20 years old I figured it would not hurt to replace it.

After reviewing the service manual and the parts diagram I ordered the parts that I could actually obtain, the gasket itself and the EPT foam seals C and D (parts #17 and #18 in the parts diagram - two of each). EPT foam seal A (part #15 ) was not available from Amayama or in North America at the time I ordered the parts; but, after looking at the service manual I thought that I might not have to replace it if I was careful removing the seal retainer from the roof panel. The seal retainer is that painted piece of trim along the outer edge of the roof panel with the black rubber lip on it that overlaps the roof panel.

Parts diagram.JPG

The service manual specifies that you remove the gasket from the roof panel and then remove the seal retainer from the roof panel once the gasket is off. With the gasket off (which is all I really wanted) it was not clear why you had to remove the retainer as part of the gasket replacement; but, that is what the service manual implied. You do need to remove the retainer if you want to replace seal A (top picture in the following diagram). Seal C and and Seal D (bottom in the following diagram) are on the outside face of the seal retainer and contact the gasket so should be replaced when you replace the side gasket. However, if you are careful you should be able to remove and replace these two seals with the seal retainer still in place on the roof.

Retainer seals.JPG

Since the service manual did not set out the option of not removing the retainer for a simple gasket replacement I dutifully proceeded to remove the retainer. That didn't go well. What is not shown anywhere in the service manual is that there was a bead of non hardening sealant (appears to be identical to 3M butyl rope caulk) between the latch mechanism and the roof panel.

IMGP4165.JPG

Roof panel showing location of sealant between latch mechanism and roof panel (after I had filled in with some 3M rope caulk to replace material that came out on the seal retainer)

There also appeared to be daubs of the sealant around the three mounting holes for the retainer and at a couple of other locations. The non hardening sealant had become embedded in Seal A and as I carefully pried the retainer off its mounting on the latch mechanism it shredded the foam (so much for saving the EPT seal). The second surprise is that the flange on the seal retainer that mounts to the latch mechanism is covered with a layer of EPT foam. Unfortunately this foam also bonded to the sealant and chunks tore off as I pried the seal retainer loose. The foam on the flange of the retainer does not appear to be available separately. I presume that it is part of the retainer assembly which lists for around $430 and then has to be color matched to your body.

The service manual also calls for 3mm thick rectangles of EPT sealer at the front and rear of the roof panels that are normally covered by the gaskets. These rectangles of foam also came apart on removal of the gasket because of bonding to the gasket.

Roof panel seals.JPG

From the parts diagram it is not apparent that Honda sells replacements for these two EPT sealers. I can definitively say that it is not part #1 which is a 15mm round piece of EPT. Honda does sell sheets of the EPT sealer in 3mm, 5mm and 10 mm thicknesses. The 3mm part number is 06990-SA5-000 (10 mm is 06992-SA5-000). I did not pre order this because I was not expecting to need it and unfortunately it was on back order locally. Doing a little Googling I discovered that EPT is described as 'super soft' closed cell EPDM foam and my local body shop supplier did have some 3 mm EPDM closed cell foam in 9mm tape width. However, the foam probably wasn't 'super soft' which likely complicated things.

Getting the remains of the old EPT sealers off of the seal retainer and the bottom of the roof panel was a nightmare. The foam came off easily, the adhesive backing was a different story. I ran my hot air gun up to 160 C and it had no effect on the adhesive. I did not want to run the temperature higher because of the risk to the paint so I ended up using pure acetone and even that required using a plastic scraper to get the adhesive off. I covered the mounting flange with the 3 mm EPDM tape that I got from the body shop and made up the (10mm x 10mm) seal A with 3 layers of the 3mm tape.


IMGP4161.JPG

Seal Retainer after the foam on the mounting flange and remains of Seal A have been scraped off

IMGP4162.JPG

Seal Retainer with my fabricated Seal A installed

IMGP4164.JPG

Seal retainer with my fabricated Seal A and 3 mm EPDM foam covering mounting flange






On the roof panel, you can clearly see where the rubber lip on the seal retainer overlaps the roof panel. With my homemade EPDM seal A I was not able to get the retainer anywhere close to the position that it had been in prior to removal. After removing and reinstalling several times I came to the conclusion that my home made EPDM seal A was not compressing sufficiently. This may have been due to the fact that it was not 'super soft" EPDM although it did not strike me as being stiff. In order to get the retainer to sit in its original position I stripped two of the 3mm layers of foam off of my seal A (it was now a 9mm x 3 mm seal) and with some grunting I was able to get the retainer back into its original position. I took the retainer off and ran a small bead of 3M caulk along the seal where it contacts the edge of the roof as some insurance against water migrating into this area.

With the retainer in place, the service manual specifies that you install the side gasket and then after everything is sealed up you install the roof on the car to check the fit of the seal retainer relative to the body (the interior trim panels are left off for this). If the seal retainer needs for-aft positioning relative to the A and B pillars the attachment screws for the retainer are no longer accessible (hidden by side gasket) so you are supposed to loosen the whole roof latch mechanism and slide it back and forth with the attached seal retainer to get the seal retainer positioned. That seemed like an invitation to more problems so I elected to install the roof panel on the car with the seal retainer attached; but, no gasket, lock the roof panel in place and then check the front and back gaps relative to the A and B pillar and end alignment with the roof panel. Based upon my gap measurements I needed a little position adjustment so I put matching pieces of masking tape on the retainer and roof panel and marked an alignment pencil line across them. Knowing the adjustment I needed in the front and rear gaps I could loosen the 3 screws on the retainer and move it the correct distance watching as a gap appeared across the alignment line. With the seal retainer correctly positioned I removed the roof panel and proceeded to the gasket installation.

The service manual calls out for the application Cemedine 08712-0004 at specific locations on the roof panel and seal retainer before attaching the gasket.

sealant.JPG

In the 2007 Honda Recommended Materials bulletin (TSB 99-030) its described as a weather strip adhesive. Cemedine 08712-0004 is no longer available. Doing a search of various Honda internet forums the consensus seemed to be that Honda weather strip cement 08712-0002 was the appropriate replacement. I can conclusively say no! I purchased a tube of 08712-0002 and on proceeding to try it out discovered that it is the world's runniest weather strip adhesive. Definitely not the product for the application described in the service manual. Going back to TSB 99-030 the usage description for Cemedine 08712-0004 described it as an alternative to 3M ULTRAPRO sealant (3M 051135-08360) which is a clear heavy bodied sealant which skins / sets up slowly compared to a lot of urethane seam sealers that I have used which skin over in about two minutes. I did manage to source some ULTRAPRO locally and it did seem to perform the function as described in the service manual. However, there was no evidence on the roof panel that a heavy bodied clear sealant had been applied in the described locations. If anything it looked more like butyl putty had been used as the sealant.

After installing the little rectangular front and rear foam pads on the roof panel as described in the service manual (note that the front and rear are oriented 90 deg to one another) and applying the ULTRAPRO in the prescribed locations I installed the gasket. Having already correctly positioned the seal retainer I set the gasket into the sealant and then placed the roof panel in place so that the weight of the panel would help set the gasket in the sealant.

The seal retainer appears to be correctly positioned based upon the edge of its rubber seal relative to the polished edge on the roof paint. The roof gasket appears to sit correctly relative to the glass and is making good contact. The front and back edges of the roof gasket line up correctly with the A and B pillar gaskets (no bunching of the gasket) and the correct overlap of that little piece at the B pillar gasket. The only unknown is whether I an going to have any long term water leakage at the seam where I have my modified A seal.

One surprise I got was that at both ends of the original gasket there were cuts in the gasket and pieces of foam had been inserted into the gasket to 'plump it out'. I thought for sure that this was an indication that somebody had meddled with my gaskets which might explain the mystery black sealant between the latch assembly and roof panel. However, after opening up the package for the new gasket I discovered it also was cut open in the identical locations.

IMGP4157.JPG

If you are going to replace the side gaskets on your roof panel I strongly recommend that you do not remove the seal retainer from the roof unless you absolutely know that you have a failure of seal A or that you know that the retainer is incorrectly positioned on the roof panel. Aside from the actual roof gasket you will need seals C and D. You will need to purchase some of the 3mm EPT sealer (part # 06990-SA5-000) for the little square pads on the roof panel so you might elect to cut your own seal C and Seal D from this sheet. 3M ULTRAPRO appears to be a suitable replacement for the Cemedine 08712-0004. If you do need to remove the seal retainer, have some butyl caulk or 3M rope caulk on hand and make sure that you have seal A or some of the 10 mm thick EPT sheet material from Honda.
 
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What an adventure!

In terms of the overall project, not such a big adventure (definitely not a Type-S Zero adventure). More of 'what a surprise' as a what I thought was going to be a 2 - 3 hour project stretched out over 2 days with running back and forth to the autobody supply shop and looking up the service bulletins on my computer. It took me at least 2 hours just to get the old adhesive off of the seal retainer because I did not want to damage the paint.

My Wife appears to have already figured out the NSX effect. If I say I am going to go out and do something on the car for an hour she just triples the time estimate. It would be interesting to know what Honda publishes for a book rate for the time to do this work.
 
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Another good reason for me to never take my roof out of the clamshell!:encouragement:

That has merit. I have adopted the flip side of that philosophy and never take the roof panel off the car except for the annual clean and lubricate the gaskets. Its way to dusty around here to leave the car outside for any period of time with the roof panel off. Plus, the black seats get toasty hot in the sunshine.

It also occurs to me that if I hadn't removed the roof panel I would never have seen the tear in the gasket and would never have been motivated to do the repair. Having owned a T roof, the coupe now has more appeal to me; but, I think model year 2000 coupes are even rarer than Zanardis.
 
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I ordered up a Carbrella when I first bought my car. That's what goes on if I stop anywhere. No dust, intense sun, or worse yet, bird crap happening in my interior. Highly recommended for all the targa drivers out there! No need to get the roof out, as my car is rarely (never) parked outside anywhere that I can't keep an eye on it.
 
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Thanks for taking the time to write this up - it will help someone or lots of someones in future. I only carry my roof around with me in case I get caught in rain. With the benefit of experience, I'm sure glad I got the Targa - I love it.

I'm trying to figure out how to retire to Saskatchewan so I can drop by Old Guy's place with questions. Although if there is ++ dust, perhaps I'll stay in humid SW Ontario.

Sincerely, another old guy.
 
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Thanks for taking the time to write this up - it will help someone or lots of someones in future. I only carry my roof around with me in case I get caught in rain. With the benefit of experience, I'm sure glad I got the Targa - I love it.

I'm trying to figure out how to retire to Saskatchewan so I can drop by Old Guy's place with questions. Although if there is ++ dust, perhaps I'll stay in humid SW Ontario.

Sincerely, another old guy.

Happy to contribute in exchange for all the useful information that I have extracted from Prime over the years. Distressingly, as of late I seem to be contributing more in the form of 'don't do what I just did'.
 
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I need to replace the back one, around the pillars not the targa itself.

One word...

Money...!!!! So expensive.
 
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Yes, very expensive and very time consuming to replace. If you just have tears in the gasket, Loctite makes a cyano glue that is excellent for bonding rubber. I have used it to repair rubber bellows and the repair has been durable. I have some around, I will check the number if you are interested. Its not cheap.

If you are missing chunks, you can make reasonable repairs using Sugru moldable rubber.

Clean the repair surfaces well with a 10% solution of acetone in water to degrease it before attempting any repair.
 
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