Mounting the top on a 68C Cabriolet

[Ed in Maine]

Before I launch into this topic, I want to say after reading all the comments on getting too old to drive a Model A scares the hell out of me. I will be 80 next year and like so many of you, it is the low back pain that makes it so difficult to get under and back up. I can never remember all the tools I will need to make an adjustment so getting under the car has to be done at least three times if I am lucky! Just keep moving and strive to do want you want to do.


I have finished the door alignment of a 31 Cabriolet after getting the body back together. Just for fun I measured the width of the top at the 3 way hinge and I see that the top is 3/4 in. wider than the mounting location on the oak belt wood. The top is relaxed on the floor and has been off the car for several years. I think I could squeeze the mounting parts together but I don't want the top to place any stress on the door pillars and screw up the door alignment. Has the top bows dried out and changed the dimensions? Is there any adjustment on the top? What has to be done to get the top to just drop in place and sit on the belt wood? Thanks for your help. Just keep moving! Ed

[Oldbluoval]

Are your door post the proper span? I’d have to look at the shop, and can, but outside to outside should be 51 3/4”, I think. Is your main bow sitting directly on top of the door posts? I have factory drawings of the top bows so I can get you the span.
Also it is very important that the top hinges line up with each other and are in the same plane.

[Kevin in NJ]

The proper span is where the door lines up with the quarters.

The door position is based on the cowl and if the doors are twisted. From the factory they were precision built on a jig. Today they are put together so they function cause we dont have wood close to the Ford tolerences.

The top wood is usually not done properly. They are copies of wood that has sagged over the years. So the top is pushed out wider then what it should be and can interfer with top iron operation. You need to mock up the top and check operation. Keep in mind the turnbuckles are NOT for adjusting position. They are structure as there is a lot of force on the top when it is up. The turnbuckles keep the pillar from hitting the door. Adjustment of the width of the qtrs is done by shimming the 2 forward uprights.

The repo top wood is wrong and will mess you up. They copied the sagged wood and that makes the top wider. Originally the top part would have had more curve to it. This can affect the top irons. I know several guys that did not understand and when them put the car together the top irons wont fold past the wood of the bow on the sides.

Look a the joint for the #1 bow. If it is the overlap joint then you want to consider getting a new bow. The factory joint was a rabbit joint (I think that is what it called) Where the upright had a finger that went in a groove on the cross piece. Classic wood makes the bow that way and I worked with them to get it closer to right.

If the center joint on your landaus is loose that will cause problems with them locking.

As you approach working on the cabriolet top you need to think more like it is a mechanical device. It is integral with the body. The distances are all set by carefull manufacture of the parts. So the header bow sets the the distance between the pins and the front of the irons. The back of the irons sets the verticle position of the #1 bow and makes it parallel with the back of the window. There needs to be a bit of compression to hold the landaus. This is done partly by position of build and partly by tightness of the top. You have to be careful as the top can pull the whole body out of alignment.

Do your door dovetails work? They keep the door from moving up and down. They must be shaped properly and move the full distance with moderate pressure from one finger. Some repro kits came with springs that were too strong. The current A&L kit should be proper after I talked with them years ago.

Also make sure your belt wood is tapered forward or you will have a line at the back of your top. The repro wood does not come with a taper. There needs to be clearance for the bow drill too.

[Oldbluoval]

The factory drawing shows the main bow having a overall 51 3/16” span
If that helps you with anything

[Ed in Maine]

Thank you all for the excellent comments. I have gotten the doors to lay up against the rear quarter panels perfectly. I would not make any changes in the width between the door pillars and mess up the fit to the quarter panels. The distance I have to the outer surfaces of the pillars is 51 3/8 in. I would guess that when I restore the top bow assembly, I should keep this door pillar dimension in mind with the top in the up and the down position. It is amazing to me that I am that close to a factory drawing without having considered it up to now. Thanks again, Ed

[Oldbluoval]

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Thanks to Kevin for showing me a path to drawings years ago!

[eystein]

Here are the relevant parts of the drawings. You should be able to work out the mating dimensions from the circled annotations