Tuesday, December 16, 2014

Painting the Trunk, Rebuilding Door Hinges the Right Way & Door Fitting Trials

It seems a little odd that the first of the “finished” surfaces on the car would be the inside of the trunk area where nobody will ever see!  But, As we continue to work the plan on this build, that is exactly where we are. 

On the heels of our last update, we began preparing the entire inside trunk surfaces for a nice, even coat of SEM 39144 Trim Black paint.  This process was started by thoroughly scuffing all of the trunk interior surfaces with red Scotch Brite pads to give the surface the tooth required for good paint adhesion.  Once the scuffing work was complete, the entire trunk area was scrubbed clean using cheese cloth and paint prep solvent.  This process ensures all of the dirt grease and wax are completely removed before any paint is applied, and the cleaning process was repeated (about 3 times) until the cleaning cloth remained clean after a thorough scrubbing of every surface.
After tacking off the trunk, the surrounding surfaces were carefully masked off to prevent over spray and we started mixing the SEM Trim Black paint in preparation for our first “cut-in” coats.  SEM Trim Black is, by definition, a single-stage paint that is simply mixed with a proper thinner and applied.  It sprays very nicely and dries to a very pleasing semi-gloss (almost flat) black that is perfect for interiors, trunks, etc.

We started painting the trunk from the inside, paying particular attention to the upper surfaces and all of the detailed nooks & crannies that would not be easy to reach through the trunk opening.  This technique ensured excellent coverage of all of the interior surfaces with no unpainted primed surfaces showing through.
From there, the remainder of the trunk surfaces were treated to three medium-wet coats of paint and allowed to dry overnight before the masking was removed. Then, another 48 hours of dry time was allowed before we began fitting the restored trunk hinges and installing the trunk lid and latch hardware. 

Next on the agenda was the rebuild of the original door hinges.  As in most Mustangs of this vintage, the original hinges were miserably worn out and sloppy, allowing the doors to droop ½” or more when opened.  Generally speaking the hinge pin size is marginal at best for the weight of the factory Mustang door and the design allowed for the hinge to flex quite a bit, adding to the wear rate of the hinge pin bushings.
Fortunately, there is an excellent hinge rebuild kit on the market that I highly recommend from Mustang Steve’s in Ovilla, TX.  Steve Wilkes has done the Mustang restoration community a HUGE favor by engineering an excellent product that cures ALL of the door hinge inadequacies in one shot.  This kit uses larger hinge pins with grease fittings to allow pressure lubrication of the pins with proper grease, larger and longer Oilite bronze bushings for added durability and load capacity and steel reinforcement tubes that stiffen the hinge considerably and provide a reservoir for the grease.  While these are absolutely not “bolt-on” repairs as some drilling and welding is required, the repair work isn’t hard, and with a little care, the entire hinge set can be rebuilt in an afternoon.  Love these!

With our better-than-new hinges ready to go, it was finally time to dust off our new door shells and see how close they would fit and how well our hinges would work.  As this was intended only as a trial fit, and mostly a hinge fit and operation verification, we didn’t yet go through a formal door fit procedure, but for the most part, the new doors hung surprisingly well for what little precision was applied to their installation.  In the end, I am pleased to report the hinges worked beautifully and each door swings silky smooth and without the slightest hint of sag.
So, how important are tight, accurate and smoothly operating hinges on a project like this?  Consider this:  If the bushings in the door hinges allow only 0.010” of slop at the hinge pins, the movement at the back of the door is almost 3/8”!  Now imagine how bad this sag would be if the bushings in the hinges were completely worn away like in our example!  Good hinges are a BIG deal and this kind of rebuild will pay enormous dividends down the road so ever cent spent here is worth untold dollars in time saved down the road.

As a natural progression, we will head into Winter here in Michigan with our focus on fitting, gapping and smoothing the doors, cleaning up and priming the rockers and getting all of the surfaces in high-build primer for finish work later in the Spring.  That is a few hundred hours of work ahead, so we’d better get cracking!
After scuffing, cleaning and tacking, the trunk was fully masked in preparation for the application of three medium-wet coats of SEM Trim Black, single-stage paint.
SEM Trim Black is our choice for trunk and interior paint and works very well as a touch-up for under-car as well.

In just about any condition we normally see, this SEM SR204 reducer works extremely well in our turbine HVLP spray equipment.
Three coats down and the trunk looks fantastic!  This shot also shows how very little over spray exists when our turbine HVLP system is dialed in.  Very little over spray on the masking and nothing on the floor or body cart.

With the masking removed, the trunk finish looks great!  We allowed a few days for the paint to cure fully before making any attempts to install the hinges and deck lid for fit.
With the restored hinges in place, the trunk finish really looks nice.  Too bad this sort of detail will never be seen when the car is completed.

With the rear seams completely sealed, the end caps and deck lid reinstalled, the back end of the car is starting to look very nice.  We will reinstall the valence and get everything in place to begin final filling and blocking when the time comes.
After a quick trip through the blast cabinet for clean-up, the door hinges are prepared for rebuild.  The Mustang Steve's rebuild kit contents are shown in the center of the photo.  Though not obvious here, the hinge kit includes new, greasable hinge pins, larger oilite bushings and reinforcement tubes.  If you look closely at the hinge on the lower left, you can see the original bushing sleeves have broken completely away from their flanges and offer absolutely no support to the hinge pin.  We are gunna fix this!
There are lots of ways to remove the original hinge pins.  Our preference is to carefully mill the expanded end of the pin off and then drive the pin free with a drift.  This has proven to be the least damaging of all methods we have tried and worth the time and effort to set up.  Also, note the sharp and unfinished edges of the hinge stampings.  This just can't be left that way and we will smooth up these surfaces as part of the rebuild.

Once the hinges are apart, a fair bit of time is spent smoothing every edge and removing all burs from the hinges parts to ensure they are smooth and clean before being rebuilt.
After another trip through the blast cabinet, the hinge pieces look far better than what they did when we started.  In this condition, we can now rebuild the hinges with the confidence that they will look as good as they will work once completed.

By just following the instructions to the letter, the lower left hinge is completed and looks as good as it works.  One change we made that is not shown here is that the angles grease fitting was replaced with a straight fitting for a cleaner look.

Here is an upper hinge fully rebuilt and ready to go.

A full set of hinges cleaned, smoothed and rebuilt to better-than-new condition.  These hinges should now last a lifetime.

The newly rebuilt hinge sets allowed us to (finally) test-fit the new door shells to the car.

Out of the box, the test fit of the doors went fairly well.  There is still a lot of work required to get the door fit to be where we want it, but the first fit is promising and the door swings beautifully on the hinges.  Far better, in fact, than any factory 70 Mustang door ever!


  1. Sven, those door hinges are pretty slick. It is a shame he doesn't make them for 67 style hinges. By the way that trunk looks pretty darn good. Looks like it laid down nice and even.

    1. Thanks Grant! I forget the earlier cars have the cast hinges and it's really a bummer because the kit works very well.

      Thank you as well for the compliments on the trunk paint. If you ever decide to try it, the SEM Trim Black lays down really smooth and easy. Their Hot Rod Black is just as nice too. These days, SEM products are just about the only non-PPG finishes I spray.

    2. I might have to try it out when I get to that point, I know for sure that I want to use the ppg on the car. Since we are on the topic of paint, what do you consider as the best epoxy formula?

    3. That is an easy one to answer! There is no better epoxy primer that I have found than the PPG DPLF epoxy primers. I am particular to the DP40LF (Gray-Green), DP50LF (Light Gray) and DP90LF (Black). These are my "go-to" epoxy primers for just about anything I do and they are relatively easy to shoot, lay nice and flat and provide a tough, corrosion resistant base for all other work.

  2. Looking good, Sven! I'm a little jealous at the progress you're making, but then again, you've been at it longer than me. I'm using PPG for the first time on my fastback. I've been a DuPont guy, but elected to go PPG since the reps here in the area are much more knowledgeable and helpful. I'm using the DP40 since I'm going for a more original "primered" look on the underside. Zero Rust will coat the interior. I'll have to check out that hinge kit. It looks nice. And as usual, your work is stellar! Have a happy and blessed Christmas.

    1. Thank you Dennis! You will love the PPG product. Just don't go into it with any preconceptions based on past experience with other products. Prep and apply exactly as they tell you and the stuff works fantastic. Best out there in my opinion and experience.

      One thing on ZR that I recommend is always top coat it with something. Even if it is only DPLF primer.

      Wishing you and your family the best and a Merry Christmas to you all!