Has anyone removed a firewall?

[N201MKTurbo]

My footwells are dented and look awful. I would like to beat them back into submission. The padding on the cabin side is glued and screwed in place and I think I would destroy it if I tried to peal it back to access the cabin side of the firewall. I was wondering how hard it is to remove the firewall. It is currently stripped down to three control cables and an air box.

If I removed the firewall I could fix the dents, rehab the tubes, clean up some wiring and replace the padding. So do I go there or not?

[Andy95W]

[N201MKTurbo]

19 minutes ago, Andy95W said:

You are not very helpful....

[Igor_U]

I see you have a J but it can’t be much different than my 67F.

 

I looked at my footwells as well, since are damaged on corners (bent), especially left one. I reckon that happened during engine removals and I might try to hammer it out.

It wouldn’t be difficult to remove the footwells, drilling out few fasteners and straighten them on the bench but firewall removal is much more involved, so I didn’t even consider that.

You mentioned the padding inside: Mine is original firewall blanket screwed with few sheet metal screws and bonded but looks like it’s loose inside footwells that I could try removal.

Removing firewall would definitely rip that.

 

I wouldn’t go there but if you do, post some pictures…

Good luck.

[N201MKTurbo]

5 minutes ago, Igor_U said:

I see you have a J but it can’t be much different than my 67F.

 

I looked at my footwells as well, since are damaged on corners (bent), especially left one. I reckon that happened during engine removals and I might try to hammer it out.

It wouldn’t be difficult to remove the footwells, drilling out few fasteners and straighten them on the bench but firewall removal is much more involved, so I didn’t even consider that.

You mentioned the padding inside: Mine is original firewall blanket screwed with few sheet metal screws and bonded but looks like it’s loose inside footwells that I could try removal.

Removing firewall would definitely rip that.

 

I wouldn’t go there but if you do, post some pictures…

Good luck.

Each foot well has 4 rivets holding them in place, but on closer examination there are about 100 spot welds on each one, they are not coming off.

I didn't consider it last night, I was scrubbing it with a tooth brush (it looks brand new except for the dents), so I didn't look at it with removal in mind, but I think it is held in by like 4 screws and some sealant. On closer examination there may be a few hundred rivets too, or not.

[carusoam]

Rich, you beat me to it...  
 

Other than a few bolts holding the engine mount in place...

And every control cable running through it...

A bunch of wires going through it...

Some heater and air ducts crossing the fire wall...

Just disconnect them all, remove all the associated rivets...

Should only take a couple of thousand hours to R&R... (?)

If you bundle up all of the work, it may make sense to include engine OH, windshield replacement, paint, and interior...

 

To get a better idea of what else can be involved... check with the Grimmy the reaper to see if he has one to experiment with...

It probably makes more sense to fix in place...

the foot wells are probably removable / replaceable...

PP thoughts only, not a mechanic...

Best regards,

-a-

[1964-M20E]

Would be nice if foot wells were held on with a handful of screws.   Remove to access other things would be easier such as the oil finger screen

[N201MKTurbo]

So, nobody has answered yes, I have done it. 
 

Is every Mooney firewall ever installed at the factory still attached?

[Igor_U]

48 minutes ago, N201MKTurbo said:

Each foot well has 4 rivets holding them in place, but on closer examination there are about 100 spot welds on each one, they are not coming off.

I didn't consider it last night, I was scrubbing it with a tooth brush (it looks brand new except for the dents), so I didn't look at it with removal in mind, but I think it is held in by like 4 screws and some sealant. On closer examination there may be a few hundred rivets too, or not.

Rich, you are most likely correct about spot weld. I forgot about that.

I believe firewall is riveted to the skin through the forward facing flange plus all the fasteners through the web holding fuel lines, heater box, harnesses, engine controls etc... 

 

[N201MKTurbo]

Sunday I’ll be back out there. I’ll give it a thorough look and report back. I got conned into flying to Chicago on Friday to do a prebuy on a 310. I’m a Mooney guy, but lately I’m a 310 guy.

[M20F-1968]

This may be of interest:

I have a firewall from my 1968 F model.  When I did my rebuild, I installed a virgin new F model firewall I found.  The footwells are in good shape.  I have many times thought that I would remove the footwells on my plane and attach them so they could be removable with threaded fasteners.  This would provide access and work space that I do not have currently (for things like changing the fuel pump or inspecting the dreaded oil screen).  

But, my airplane is now together and I do not plan on removing the engine for a very long time.  I would be willing to sell the firewall if you were interested. 

Removing the firewall is not something you take lightly.  The firewall flange is likely wet shot with PRC and would be a pain to remove, and also would give rise to some needed exterior painting.

John Breda

[N201MKTurbo]

5 hours ago, M20F-1968 said:

This may be of interest:

I have a firewall from my 1968 F model.  When I did my rebuild, I installed a virgin new F model firewall I found.  The footwells are in good shape.  I have many times thought that I would remove the footwells on my plane and attach them so they could be removable with threaded fasteners.  This would provide access and work space that I do not have currently (for things like changing the fuel pump or inspecting the dreaded oil screen).  

But, my airplane is now together and I do not plan on removing the engine for a very long time.  I would be willing to sell the firewall if you were interested. 

Removing the firewall is not something you take lightly.  The firewall flange is likely wet shot with PRC and would be a pain to remove, and also would give rise to some needed exterior painting.

John Breda

Yea, I went out and looked at it yesterday and there are about 200 rivets. I’ll just live with the dents.

[Yetti]

Seems like a good body man with a hammer could fix you up.  Maybe two. For less work than removal of the FW.  I have quite impressed with the paintless dent removal tool after the subie fell fate to a hail storm.   Not sure how well it would work on stainless.

[N201MKTurbo]

On 1/8/2021 at 10:56 AM, Yetti said:

Seems like a good body man with a hammer could fix you up.  Maybe two. For less work than removal of the FW.  I have quite impressed with the paintless dent removal tool after the subie fell fate to a hail storm.   Not sure how well it would work on stainless.

If it was that easy, it would have been done already. The problem is the insulation mat on the cabin side. Short of cutting holes in it, the only way to get it off the firewall is to remove the firewall.

Besides, can you imagine swinging a hammer down in the footwell? I was thinking of using a rivet gun with a flush set and have someone on the outside with a body dolly.

Edited February 21, 2021 by N201MKTurbo

[Yetti]

maybe take the footwells off.  Which would then give you access to the inside and outside through the hole.