HM2017 Build

[Paul Proefrock]

The half shafts came from The Driveshaft Shop.

Many guys buy aftermarket T-Bird half shafts, disassemble them and then re-assemble using the shorter inner shaft. But you have to know how to rebuild half shafts to be successful. There are some tricks to taking them apart.

Paul

[Jeff K]

Thanks Paul, that’s good information.

[Jeff K]

Paul, the half shafts on your car came from The Driveshaft Shop but the ones on my car, which are based on the Thunderbird differential, did not according to them. 

The Driveshaft Shop wanted $1300 for a pair of custom axles. I found a shop in Salt Lake City that works exclusively on CV joints that said they could rebuild them. After inspecting mine, they said they were in good shape but needed more grease. They repacked them, put new boots on and sent them back. I had a local shop rebuild my center section. It required new bearings and a new gear set. They said whoever setup the differential originally didn’t know what they were doing.  I had to replace the axle nuts also since they weren’t the correct ones. Too bad I had to spend over $2K to fix something I shouldn’t have had to fix. It’s maybe best that the previous iteration of Hurricane went out of business. They were cutting too many corners.

Just went for a long drive and the rear end is working as it should. Just about time for the 500 mile oil change. My plan for now is to put some miles on the car and continue to tinker with it. I’ll worry about paint in a year or two. That’s it for now.

[Jeff K]

It’s been a while since I’ve posted any updates, mostly because not much has happened regarding the build.  I drove the car over the summer and worked out some bugs.  I now have over 1200 miles on the car and overall, I’m really happy with how the car is turning out.

In December I took the body off for the last time. I tidied up some wiring, applied bed liner to the underside of the body and did some other final teaks while the body was off.  My plan from early on was to bond the body on permanently.  I had read forum posts from people who had done the same thing saying it really made the car feel solid.  So, after triple checking the body fit, I glued the body down onto the firewall, the rear cockpit tub and to brackets I installed on the upper frame.  You can see one of the brackets in a picture below.  There are 3 brackets per side.  I kept track and this was the 20th time I had removed and installed the body.  Glad to be done with that part and be done with the body buck.

Next, I fiberglassed the body to the trunk liner in the back and to the cockpit tub sides.  I reassembled the car still with the primered body.  I plan on driving it this way again this summer and next winter, think about having it painted.  I took the car out today for the first drive since gluing the body down and I can really tell the difference.  I wasn’t expecting that much improvement in the stiffness of the car.  It feels very solid now.  So glad I decide to go that route.  It was a lot of extra work but I think worth it.

[Greg K]

Nice work Jeff. When I fit and fastened my filler panels to the trunk and body, makes a big difference oand more solid feel overall. I filled and bonded the foot boxes with EPDM backer rod and seam sealer up top and around. I thought about doing glass but went the route I did. Enjoy.

[Jeff K]

Early on in my build, I could see that there was going to be an issue with my IRS setup. The frame rails above the suspension are close to the upper A-arms while the car is at rest. This would limit the upper travel of the suspension. The shocks have about 4” of total travel. Right now, I have the rear ride height set so the half shafts are about level. At this height, I have ~2” of downward travel and ~1” of upward travel at the shock before the A-arm contacts the frame. The distance from the ground to the top of the wheel opening is 26-3/4” and I don’t want to go any higher due to ascetics.

Last summer as I was putting miles on the car, I noticed the rear suspension would bottom out when carving corners on windy roads and on some higher speed bumps. Earlier I had added rubber bump stops to prevent hard contact of the A-arms which helps.

After studying the layout, I determined I could modify the upper control arms to add more clearance to the frame.  This should solve the problem I figured. Now I came to the next design error.

I removed the upper bolt from the upper A-arm and axle housing so I could cycle the suspension higher to determine how much to modify the A-arm. As I lifted the suspension, it started to bind, preventing it from going up. I eventually determined that the half shaft was at full compression and was bottoming out internally. Turns out the half shafts are at least a ½” too long to allow additional upward travel. There’s no issue with the suspension going down due to the suspension geometry. Now my only option would be to buy new shorter half shafts for $1300 which in turn would allow me to modify the upper A-arms. That’s not going to happen right now so I’ll live with it the way it is.

I’m curious if any other owners with the earlier Ford Thunderbird type IRS have had the same limited travel issue. I don’t believe too many were installed. It looks like the later model IRS units installed don’t have the same issue.

[Paul Proefrock]

Jeff,
What track dimension did you set your suspension to? Try screwing the rod ends out to increase the effective length of the control arm. Also check your axle nut ends, where they go into the hub. Make sure there isn't an extra spacer in there.

There was an issue years ago, with the axles being made too short and they were pulling apart on Factory Five installs. DriveShaft Shop lengthened all of them and then got into issues on other suspensions that used the same axle (Hurricane did). There is a fix to this by re-assembling the axles to shorten them effectively. Take a read of this thread on the issue

https://forum.hurricane-motorsports.com/forum/index.php?topic=2301.msg22524#msg22524

Paul

[Jeff K]

Paul,
That is great information. I’m glad to hear it isn’t just a problem on my car.
Regarding lengthening the control arms, I would only be able to extend the lower control arm rod ends since there is no adjustment on the upper control arms and this would seriously affect the camber.
My best option is to do what you did and move the trilobe down the shaft. That seems like a fairly painless modification and a ¼” shorter is better than nothing.
Thanks very much for the reply and information.

[Jeff K]

I wanted the look of the oil cooler in the radiator opening but given that my car is only street driven, I didn’t need a functioning oil cooler.  So, I opted to do a faux oil cooler, which gets me the look without the hassle of running hoses.

I found a 13-row cooler, hose and fittings online for $100. I went with the 13-row cooler to fully fill up the opening in the body. Using the cooler as a guide, I created a cardboard template that I then used to transfer the port and mounting screw locations to the front radiator aluminum panel in the car. I measure many times to hopefully get the holes in the correct location. Once marked, I used a step drill bit to create the port openings in the panel. I then mounted the cooler to the panel. To secure the bottom of the cooler, I decided to attach it to the fiberglass as opposed to securing it to the radiator support with bars. I made some spacers to fill the gap between the bottom of the cooler and body. The cooler is very solidly mounted.

I made the AN hoses to the desired length with 90-degree fittings on both ends. I then used the step bit to create holes in the side panels to the right and left of the radiator. I installed the hoses to the cooler ports and then secured the upper 90-degree fittings to the side panels using block-off caps on the opposite side of the panels which sandwiched the panels between the fittings. I’m pleased with the results even if it is non-functioning.

[Jeff K]

For tightening and loosening the knockoffs on my car, I’ve always used a 2x4 and small sledge hammer because first, I don’t have a lead hammer and second, I’d be afraid of swinging a hammer that close to my rims in case I missed. My friend who has a cobra said that he has hit the rim on his car with his lead hammer without damage but I’m still leery.

My method works but I really wanted a tool that could be used with a breaker bar or torque wrench for a more controlled method of tightening and loosening the knockoffs. I see there are various tools available for purchase but I thought why not fabricate my own.

I came up with a design, bought some metal and even used part of an engine stand I had around to make the tool. It turned out to be a lot of work since I don’t have some of the proper tools. I made some leather covers to protect the knockoff wings from where the tool contacts.

I initially thought I should be able to tighten the knockoff further with the new tool. That was not the case. I marked the knockoff current location, loosened it and then tightened it with the tool to over 300 ft-lbs of torque but I was short of the original mark. I had to add my floor jack handle to the breaker bar to get the leverage needed for this torque. I got very nervous applying that much torque to an unproven tool. And then my friend asked if I really planned on carrying all that stuff in my trunk in case I needed it on the road. Good point.

So, after all that fabrication work, I’ll probably just stick with my current method for tightening and loosening the knockoffs. I'm not sure how much torque my 2x4 and hammer applies but it’s obviously enough.

[Jeff K]

Looks like I solved my rear suspension travel problem. I had two problems; one being that the half shafts were too long and binding during upward suspension travel and the other being that there was limited upward suspension travel due to the upper A-arm contacting the frame.

To solve the A-arm contacting problem, I modified the upper A-arms to allow for more clearance with the frame. I accomplished this by basically reshaping the A-arms. I made sure the hole-to-hole length of the A-arm didn’t change to maintain correct suspension geometry. I realize this modification changes the strength of the A-arm but I suspect it’s a minimal difference.

For the half-shaft problem, my plan was to incorporate the fix that Paul had suggested earlier. But after I took the half-shaft apart, I realized I didn’t have that option with my half-shaft design. The trilobe was already at the end of the splines. One of the attached pictures shows where the trilobe was contacting inside the axle housing. What I decided to do was to carefully grind back some of the shaft to create clearance for the trilobe to slide further down the splines. I realize I wouldn’t have as much spline engagement but that was a compromise I was willing to make. I was able to grind a new slot for the C-clip to lock the trilobe in place. I gained almost a ¼” with this modification which was the best I could do. Hopefully it would be enough.

As I was installing the A-arm on the passenger side, I determined that I did not have the same half-shaft binding problem as I did on the driver side. With no spring installed, I was able to raise the suspension all the way up with no binding. After making measurements, I determine that the center differential was not equally centered between the hubs, being a ¼” closer on the driver side. Then I remembered that early on in my build, I had corrected a clocking issue with the differential. In making that correction, the differential moved towards the driver side probably about a ¼”. Fixing one problem had created another. Having said that, the half-shafts are still a ½” too long. There’s no reason that there should be only a ¼” of margin.

After reassembling the suspension, I took the car out on a driver over the same roads I had had issues with before and there was no binding and the suspension never bottomed out. Overall, I’m happy with the results.

[Jeff K]

Half-shaft pictures.

[Jeff K]

More half-shaft pictures.

[Jeff K]

It was mentioned to me before in the forum that the front lower A-arms on my car did not have the welded in reinforcing gussets on the curved rear legs. Later cars already had these gussets installed from the factory.  So just to be on the safe side, I decided to install them.  One less thing to worry about.

[Jeff K]

I wanted a tonneau cover for my car to cover the interior when it’s parked, both to protect it from the sun and to keep prying eyes out. At first, I thought about a traditional tonneau cover, the type held in place by lift-a-dot fasteners but then I watched Pete Howland’s excellent YouTube video of the tonneau cover he purchased for his car (HM2029) and thought it would work for me also. Pete was nice enough to included the contact information for the manufacturer in his video. His cover was made by Phillip and Kay Deal, a husband-and-wife team in South Carolina. They are retired and this is a side business for them.

I contacted them and started the process to have a cover fabricated. Each cover is made to order. A fabric template was mailed to me and I marked features on the template such as the roll bar location, rear view mirror location, tie-down grommet location, etc. I then mailed the template to them and then several weeks later they mailed me the completed cover.

When I installed the cover for the first time, it fit perfect. It took only a few seconds to install. It’s held in place by a couple of bungee cords. It’s not designed to be installed when the car is moving or being towed. But it’ll work perfect for when the car is parked. The cover cost $275 and $20 for a storage bag plus shipping.

Here’s their contact information in case anyone else is interested:

Phillip and Kay Deal
wpdeal@gmail.com
864-895-5034

Here’s a link to Pete Howland’s YouTube video where he discusses his tonneau cover:
https://www.youtube.com/watch?v=vAHleF-xRRE