8/8/2005 Rev .75
The Model A Rumble Seat and how it is put together.
There have been many questions on rumble lids and the parts needed to put together
a rumble seat. I had to answer that question for my cabriolet since I started
from nothing. What I had learned is that the vast majority of all the cars I
have looked at do not have the rumble parts put together correctly. What I have
found is the assembly of the parts is not too hard, but learning what is needed
for your car may not be easy. The differences between a trunk car and a rumble
seat car are only a few parts. Obviously there is the rumble hinges. Then there
is a the curved inner panel and the two rumble stops. Attached to the curved
inner panel is a brace for the spare tire. When converting from a trunk you
will be removing the trunk inner panel replacing it with a curved inner panel.
You will also have to put on the two rumble lid bumpers and centering parts
that cover the hinge pin holes in the body. There is also a different latch
for 30-31. Please keep in mind I am trying to stay with verifiable facts with
with I write. If you catch an error or have some information I could add please
email me. I will also touch on the lower rear panels. Please keep in mind that
when I talk about a reproduction rumble lid I am talking about the one made
by Brookville as that is the only one I have worked with.
There are several variations of rumble setups through the years. All the 28-29 coupe models and all years of cabriolet used the same lower rear panel, short rumble stops and curved inner panel. These cars used the shorter curved inner panel and lower rear panel and the lower rear panel does not have a bead at the bottom. The ‘28-29 roadsters used the same parts as '30-31 Coupe/Roadsters, except the lower rear panel has no lower bead. The 30-31 all coupes and roadsters used a taller yet curved inner panel and the lower rear panel has the beading on the bottom. The 30-31 cars used the taller rumble stop. The cast iron bracket that is riveted to the convex side of the curved inner panel is the same for all years.
I would recommend going to Bob Johnson's cabriolet web site and look at the pictures of his pieces of his cabriolet. This will give a good overview of the parts from different angles. Beside Bob has put together a great site that probably has more information hidden in the nooks and crannies than you might expect.
Here is Bob's web site: http://www.cabriolet.modelahouse.com/cgi-bin/bobs68b
The rumble lids are different from 28-29 to 30-31 see the pictures that Marco Tahtaras made up to illustrate the differences. They are physically the same dimensions, the problem is with how the gutter area had to be formed. The 28-29 lids latched up inside the gutter area and the handle is closer to the edge. They also have a bulged out area in the inner lid structure at the upper front center area which requires a dip in the gutter channel. This was changed for 30-31 and the catch was moved to the back edge of the gutter and the gutter no longer had this dip. What this means is you can not use a 28-29 lid on a 30-31 body. But you can go the other way, in fact there is a service bulletin explaining how to mount the later replacement lid on the earlier cars.
If you are using an original lid use original hinges as the original hinges are VERY available. If you can not find them you have not looked.
The repro hinges do not fit the area in ANY dimension! It appears the repros are just direct castings with low quality cast iron of originals. The problem with a direct casting is shrinkage, the metal will shrink when cooled and no one bothered to make an oversized master. You will find the article in the How to Restore Your Model A series on doing a rumble lid conversions, the nut plate pattern is not scaled correctly. You should make the nut plate based on using the hinges you are going to use. The area where the hinge fits into is a complex curve. The original hinges fit that area like a glove, the repros are not even close. I can not say it enough if you have an original lid get original hinges.
Make sure you mount the hinge brackets in your car and measure the distance
between them and then make sure the hinges are the correct width when mounted
on the lid. If you buy the reproduction lid from Brookville than you will want
to make sure that you specify the distance you need between the hinges. The
repro lid has the captured nuts set up for repro hinges so you want to buy the
repro hinges at the same time. If you want to use original hinges with the repro
lid you will have to send them the original hinges and have them fit the holes
to your hinges. Do not even think for a moment that you can make an original
hinge fit the screws set up for the reproduction hinges on the repro lid. Do
not think that you can get the repro hinges to fit the original holes of an
original lid. If you are trying to convert an original lid to a rumble lid you
will find that the reproduction hinges do not fit where they are supposed to
go, I predict you will learn many new curse words trying to make them fit.
If you are using a repro lower rear panel. It is flat across the top so the distance from the lower corners of the lid and the panel are much closer than the original. This tighter gap in the corners will allow the corners to touch while moving causing paint to chip (look at the cars at car shows and you will see what I mean). Also the repro panel does not have the hole for the spare tire mount in the center. All original panels had the hole for the spare tire mount and it was blocked off with a button if there was side mounts. This button would have been painted body color on factory car side mount cars.
If you are using the repro lid then you may find the gaps are tight at the top and bottom. It is even worse when you have a repro lid and a repro lower panel. When you are fitting the repro lower panel you may want to make the holes a bit larger and sneak it down a bit to increase clearance. This will reduce the chances of the two parts hitting while driving and chipping the paint. The original lid lower rear section had a slight curve up in the lower corners and the original lower rear panel curved down about 1/8".
I have a discussion on the repro lower rear panel you might want to look at:
The repro curved inner panel may not fit very well, take some time to fit it. Mine did not seem to line up with any original holes on the side braces so I drilled new ones. The curved inner panel has the cast iron brace riveted in and a rectangular hole. The area where the brace gets riveted on might be depressed rearward some which is not obvious. The depression can be seen in pictures of Marco's car which is a 30 roadster. Not all bodies would have this depression and I have no idea which one would. Here is a picture of the curved inner panel on Marco's car:
The curved inner panel pictures sent to me by Tom Moniz show the cabriolet curved inner panel as being flat. See the next picture:
Note how the how the screw holes along the long edges are curved and countersunk.
The reproduction panel with an original cast iron brace would not fit correctly on my car. The top the the cast brace was not up against the inner spare tire brace. This may be because of something being off while building my car or this could be a common problem. I created a depression to make the part fit.
The forward long edge of the repro is flat, not curved like the original, and the holes are not countersunk. I must mention I missed on the rectangular hole and it is a bit longer than it should be. That hole was mostly a guess and done before I had come across a beat up original curved inner panel from a 30-31 coupe.
Finding original curved inner panels that are usable is not easy, I and others have tried. I think finding a good original lower rear panel is even harder. If you are using an original rumble seat riser than you might also have to fill in all the holes of the repro curved panel where it attaches to the original seat riser. The reproduction curved panel my brother used to do a rumble conversion on his car is much worse than the repros you can buy today.
There are two types of rumble lid stops. Look at the picture Tom Moniz was kind enough to send me. On the left is the taller later style used in 30-31. The one on the right is the shorter one used in 28-29 and all cabriolet. There are two repro brackets that I know of on the market. The tall one is reproduced in aluminum and the short one is stamped steel. The short stamped steel rumble stop needed some minor alterations at the bend point in the area where it mates with the bend of my repro curved inner panel on my car, I do not know how it fits original metal.
The underside of the rumble riser has a re enforcement welded in where the two forward holes of the rumble stop bracket go through the riser. This is a pretty important re enforcement to have in place if you are doing a rumble conversion. It had a bunch of spot welds holding it in place on the original.
Rather than try and find a decent rumble lid and after talking to several experienced restorers I bought the rumble lid made by Brookville. The Brookville does work, but it may not work out of the box. The first one they shipped me I made a bad assumption, they said all the original Ford parts fit. The original hinges just do not fit in nice and only one screw hole lines up per side. I called Brookville (great people to deal with) and they said that all there lids were made for repro hinges as that is all they can get in quantity. I bought repro hinges. I got the repro hinges and found the lid was made such that the rumble hinges were about 2" too narrow for the mounts in the body. You can not bend the reproduction hinges as they will break very easy I was not even trying and had one hinge break and you could see that the cast iron had a flaw at the break point. I sent lid #1 back and they sent me a new lid with new hinges set up to fit the distance between my hinge mount points on the body. They paid shipping both ways, great company to deal with. Now I start to test fit. I found that the latch was mounted too low and the front lip of the lid was too low. Plus because the screw holes were too low the collar on the latch that screws inside the lid did not touch the bottom of the sheet metal. This means that when a rumble handle is install it will pull the sheet metal down causing a depression around the handle. Then I found to get the lid to line up correctly for my body (remember I had to do a lot of work on mine) I needed to elongate the rumble hinge brackets that mount on the body.
Here is how I relocated the latch in the rumble lid and a way to locate the holes to convert a original trunk lid. I filled in the two screw holes with my MIG welder and pre-drilled them higher. Setting up the latch is based on first making the 2 screw mount holes. The location of the these holes is governed by two facts. The handle must be centered left and right. The top part of the latch body must be touching the outer sheet metal so that the handle is not making a depression when installed. Once you set the screw holes you can use a dremel with a fiber cut off wheel to make the rectangular opening. Once the latch is screwed into the lid you can make a center mark on the outer skin and drill the hole for the handle. Setting up the latch takes a while and a little thinking, you have heard this before: measure twice cut once.
The reproduction lids are not welded together they have only folded the seams together. The lid will actually flex some. This is important because after you get the car set on the frame and the body aligned you install the lid, warp it to best fit to the body, and place a few (Ford did 4 on one lid I had) welds to lock the top and bottom to shape that works for your car. The original welds look like they were done with a torch and possibly no rod. Aligning and setting the rumble lid is not a one person job and should only be done when the body is set up on a frame and everything else is aligned.