FE-FC Holden Discussion Forum

Hi All,

About to tackle sub frame rust repair. Taking it off the ute so I can give it the once over. I see that there is a sealant up where it attaches to the firewall. Is this necessary on reassembly and if so what suggestions have we got.

Cheers

Rod

Rod
I am going to use a windscreen sealant that would seal but not set hard something that did not contain a silicone.
I have not checked out what is available as yet

Crowbar

Rod

Can't recommend any brand but whatever compound you use it should not harden and should have a skin form on the surface to allow for paint to be applied.

If ever you attempt to remove again it is possible without a lot of force.

Cheers

Craig

I used sickaflex the first time i di my re build and it cracked a little ..


So we use at work Wurth windscreen adhesive i hate wurth mainly the rep.

 but this stuffs awesome sets but is still flexible where as some stuff wont set so you get crap on your hands still.

And yes its black but you can paint over it.

Try it we actually use it to hold gas strut mount on mirror or grained S/S doors so you dont get a weld stain or mark this stuff will hold a 500 newton strut
and will not budge or move will actually bend the metal trying to remove it.

You could seal it with mastic let it dry up for a few weeks then go over the top with 3M  drip check so it can be painted over ......FC427....

What happens if you need to pull it apart later?

The goal here is just to keep the water out, I just use black mastic windscreen sealant, can't recall the brand, but any windscreen joint would sell you a cartridge.

Gary

Thanks everyone for you advice. I am not far away from putting the subframe back in. A job I expected to finish a couple of months ago.

While I have the front end off and have easy access to a lot of joints I plan on sealing them and every "knook and cranny". I had a look at the front gear box cross member and I was shocked to see the join between the floor ribbing and the cross member in a couple of places. Should I fill this in so no water / dirt can get into the cross member? There is also what seems to be a drain point where the cross member attaches to the inner sill. What are your thoughts on seal this?

Thanks Again

Rod

Rod, You can certainly seal the top of the crossmember where it meets the floor, but absolutely keep clear the drain spaces where the crossmember is attached to the sill. I think you already worked this out, but no harm in confirming.

Ken

Thanks again as always Ken. Not far away from putting subframe in. Should there be a drain hole on either side of the subframe for the panel that runs down the fire wall and meets the side rails. One side seems to be welded across while on the other side where I had to put in a donor section wasn't welded and a hole was present. Any thoughts.

Rod, yes there should be - usually at the back there is a gap in the welding which allows water to exit the upper subframe rail if any does get in there.

Ken

Hi All,

Sorry to bring up an old thread from years ago when I last installed a subframe. Last time I ended up using Butyl Mastic whci I plan on doing on the FE, hopefully this weekend.

Well us Vics are in lockdown again and what better time to put the subframe on this weekend. Last night I decided to go to Bunnings to get some Butyl Mastic. While I was at it, I thought I would clear the local supermarket out of toilet paper - nah, only kidding! Bunnings didn't have Butyl Mastic but had D Mastic. I am not sure if there is a difference between the two, therefore didn't purchase it.

I can't remember how many tubes (400g - Chaulking Gun Tube) I used last time. Can anyone direct me how many tubes they have used. I have one tube at home but don't want to use it to find halfway into the job I don't have enough.

Oh and I have had a look online and can't seem to find Butyl Mastic from Bunnings, Supercheap, Repco etc.... Any suggestions would be appreciated.

Have a great weekend. To all the Vics I hope you can use this forced time on you "old girls".

Have a ripper Rod

According to Selleys, butyl mastic is a synthetic resin, butyl rubber based mastic which forms a smooth tough skin, but remains permanently plastic underneath. It is available in 3 colours – White (off-white colour), Black and Grey. D-mastic is an alkyl resin modified, oil based caulking compound. It forms a tack-free skin on the surface when exposed to air but remains soft underneath. D-MASTIC is black in colour. 

Selleys mentions automotive gap sealing for both products.

D-mastic is for little to no movement. Butyl mastic will handle up to 8%.

I reckon you will be OK with D mastic if Bunnings no longer sells butyl mastic.

Cheers,
Harv

Rod,
I used Sellys butyl mastic on my FB ute wherever metal sheets were sandwiched together, including the subframe skirt to firewall. One tube is just enough, do better to have another on hand as you say.

I had trouble getting it lately from the big outlet you mentioned, and had to settle for the off white, having started out with the grey. I had to visit three different stores before I found the last lot at Edwardstown.


Sent from my iPad using Tapatalk

Thanks Harv and Clay.

I ended up using the D Mastic. To be honest I think it is more workable than the Butyl Mastic. It seemed to clean up better as well.

An FYI, I ended up using about 80% of the 400g tube. Admittedly, I would have used more if I used it to seal the edge of the mated joints but I plan on running a very thin bead of sikaflex along these lines.

Thanks fellas for your insight.

Cheers Rod