How to Inspect and Evaluate

For suspensions, there are two main concerns: bushings and wear. If the car was used in a colder climate, corrosion may also come into play. The simplicity of the suspensions used on early Mustangs pretty much limits the major concerns to deteriorated rubber bushings and worn metal components like adjusters. The former are generally the most noticeable because the rubber often can deteriorate to the point of collapse, thus affecting the vehicle’s handling and/or causing clunking or other noises. The latter, are generally more subtle in their effect.

This Tech Tip is From the Full Book, HOW TO RESTORE YOUR MUSTANG 1964 1/2-1973. For a comprehensive guide on this entire subject you can visit this link:

LEARN MORE ABOUT THIS BOOK HERE

SHARE THIS ARTICLE: Please feel free to share this post on Facebook / Twitter / Google+ or any automotive Forums or blogs you read. You can use the social sharing buttons to the left, or copy and paste the website link: https://www.diyford.com/inspect-evaluate-mustang-restoration-projects/

The front strut rod bushings definitely perform critical functions yet are often improperly maintained. These are mainly rubber parts; they are very definitely affected by time and the elements, as well as wear. These bushings locate the lower control arms and thus directly affect the path of the vehicle. Too much play in either bushing, or even too much of a difference from side to side, can have a very negative effect on handling and, more often, on braking. A car that pulls sharply to one side under braking may not have any problems with the brakes themselves; rather the strut rod bushings may be causing the issue. These parts don’t have a very large range of movement but they do still become loose. This looseness causes the car to lose directional stability, especially during braking when the rear bushings are in compression. At a minimum, these bushings should be inspected and adjusted during any restoration project. Considering their cost and accessibility, just replace them and install a new, properly adjusted set. Remember that any changes to these bushings will also require the wheel alignment to be readjusted because the location of the lower control arm will move with the adjustment/ replacement of the bushings.

Tires may wear unevenly, and the steering wheel may pull to one side while driving, for example. So it’s necessary to perform a thorough visual inspection of the front and rear suspensions while they are on the car. At least partially disassemble them in certain areas to make sure the components are healthy. Ball joints and lower control arm bushings in particular can appear to be okay unless they are checked in a specific manner.

The anti-sway bar bushings and end-link bushings usually require attention. It is fairly common for the bushings to partially collapse and/or tear, often to the point of causing a clunking from metal-on-metal contact. The end-link bushing can also fail in such a manner though this is less likely. It is generally more noticeable, however, as degraded handling usually accompanies the inevitable noise. A more common scenario is that the bushings wear unevenly to the point that excess play is created. This negatively affects the vehicle’s dynamic behavior, particularly during quick changes of direction. There may or may not be a noticeable increase in noise to go along with this handling change.

Our rear suspension was in pretty good shape to begin with. The car drove well and all of the original rubber bushings were in decent shape. The shocks had already been replaced at least once and showed no signs of leaking. If we were on a really tight budget with a daily driver, we could just do some cosmetic touching up and reuse the shocks and bushings, at least for a while longer. Clearly, this would not do for a show car unless it was a survivor car. For our weekend cruiser, however, we will replace and upgrade many parts for better performance. We replace them with parts that are similar to the factory parts but provide much better ride and handling. And these parts don’t adversely affect collector value of the car. The U-bolts, the spring plates, and the rubber axle bumpers mounted in the frame are the only factory parts we keep.

The spring-eye bushings on our car were in good condition and didn’t need to be replaced for daily-driver duty. And all of the mounting brackets, shackles, and fasteners were in good shape too. There was some surface rust but no serious corrosion. It is critical that the areas around where the springs mount to the car are free of any significant rust; this could cause big problems if the springs were to pull out. Another common issue is damage from improper jacking, which we luckily did not have. Problems such as these, which affect the structural integrity of the vehicle, must never be ignored and must be fully repaired before the car is restored and driven. Ideally, vehicles with such issues would be passed over in favor of using those in better condition as the basis for restoration.

Also, replacing many parts while the car is being restored reduces problems and cost later on. Bushings, bearings, and the like are relatively inexpensive and usually pretty simple to install, so replacing them is a form of cheap insurance against unexpected failure. Give shock absorbers similar consideration. If there are no visible leaks or other damage and the damping action is acceptable, it may be possible to retain what you have, especially if they were recently replaced or are the original shocks (in the case of a survivor or show car). In most cases, however, there are significant ride quality and handling improvements if the shocks are upgraded.

From the factory, the welding around the shock towers is, quite literally, spotty. This causes stress risers, which can lead to cracking and metal failure as the car ages. Aggressive driving and/or harsher climates can further compromise shock tower integrity. The simple remedy? Continuously weld the stampings that were only partially welded by the factory. This greatly enhances the structural integrity of the front of the vehicle, improves ride and handling, and prevents cracking. With the engine out of the vehicle, this is pretty easy to do; it probably should be left to a professional if you’re not too proficient at welding. Proper preparation is a key. Any paint or undercoating must be completely removed to expose bare metal. Close any existing cracks and properly align the parts before further welding is done. Be sure to weld the inner and outer edges of each stamping and weld all accessible areas as shown. Make sure all other parts have been removed from the immediate area: the shock towers will get quite hot. The area, of course, also needs to be primed and repainted. The backside of the shock towers need to be re-primed and painted as well. We removed all of the burned paint and undercoating to get the best possible coverage. We also removed the accumulation of dirt that tends to build up on the flat horizontal surface beneath the control arm. After many years of dirt being thrown off from the tires, it is reasonable to expect this buildup to occur. However, drain holes in the corners of this area often get clogged so water and moist dirt remain in the area. This can lead to the steel rusting through, which is very undesirable in such a highly loaded area. We removed all of the dirt and opened the drain holes a bit to help prevent them from clogging in the future. This area sees much dirt and moisture, it is especially important to use a very robust primer before applying a paint and/or undercoating combination that will prevent any future rust issues.

In any case, the peace of mind gained from replacing an unqualified item with a new part of known quality is worth the relatively minor cost. And when a part is rebuilt to retain authenticity, using new consumable/wearable components generally does not detract points from scoring in a show setting. Suspension parts should only be reused when they are known to have been very recently replaced by known good components, recently rebuilt, or are being kept in original condition in a survivor car.

Many early Mustangs have various metal shields, such as this one, to protect fuel and/or brake lines as they cross over underbody surfaces. The idea was/is to protect the line from scraping the ground (or a speed bump, etc.) and then collapsing or leaking. You can imagine the problem if a fuel line got snagged on something and gasoline was sprayed onto a hot exhaust part. Those doing show-car restorations reinstall these parts anyway for the sake of authenticity, yet other restorers shouldn’t ignore them. We decided to install subframe connectors and we won’t be able to use this particular fuel line shield because it interferes with the subframe connector. However, this is not a problem because the subframe connector itself provides even better protection from anything that might be able to contact the fuel line.

Similar to the extra welding around the shock towers, the chassis areas must be stripped of paint and any other material and must not be overly rusted so the subframe connectors can be properly welded to the frame for maximum strength. Also, as with the shock towers, the attachment plates are welded completely around, rather than simply spot welded in just a few places. This ensures the best performance and durability of the subframe connectors, plus it eliminates gaps that could allow moisture to seep under the attachment plates. Finding the proper location of the connectors involves a bit of trial and error because they have a tendency to rock or move the opposite end when one end is pushed fully on. The best location (at both the front and the rear) is the point where the attachment plates have the greatest amount of engagement with the subframe stubs. The connectors should be relatively level and as snug to the floor of the car as possible. Don’t be afraid to push up on the floorpan a bit to get a better fit. Any fuel or brake lines that must pass between the subframe connector and the body should be moved to an area that has greater clearance to avoid pinching the line(s). Our subframe connectors were manufactured by Global West Suspensions and are intended for a welded-in installation. These and other such products from other manufacturers can be simply bolted in as well, though this is not recommended. A bolted-in setup never matches the strength and effectiveness of a welded-in installation of the same part. Others who may not want to do any welding because of concerns over the potential impact on resale value need to consider that even welded in subframe connectors can be removed and the welds ground off to the point it would be difficult if not almost impossible to know they were ever there.

The rear suspension is considerably less difficult to evaluate than the front. You’re basically limited to sizing up the bushings in the leaf-spring eyes and the condition of the fasteners like U-bolts and shackles. There is rarely a problem with or damage to the leaf springs themselves. They may need some cosmetic touch up, but if there is a problem with the springs being excessively corroded or having lost their shape, they are generally replaced. Only in a survivor or show car should the possibility of refurbishing and reusing deteriorated leaf springs even be considered. In our case, we went with an upgraded set of springs. In most cases all that likely is needed are new bushings, possibly shackles, and paint. You also need to determine whether or not to upgrade the factory setup for improved performance. This isn’t an option for a show car (authenticity); and, for a daily driver, the cost may not be justified if the benefits are not needed. For our weekend cruiser, however, this is beneficial and cost effective, even though we have elected to only pursue the subtle upgrades.

This photo of a finished installation of the Global West Suspensions subframe connectors shows that they provide extensive stiffening to the vehicle structure and generally do not present ground clearance problems. Other components, usually the exhaust, often hang down lower and would contact the ground before the subframe connectors. Our 1968 fastback will not be used aggressively, so we only installed the subframe connectors alone, without the optional jacking rail kit. Weight gain in either case is negligible and is low and centered in the car.

Regardless of your type of restoration, one of the best things you can do to improve both vehicle handling and braking performance (and long-term durability) is upgrade the front strut bar bushings to a harder/higher durometer rubber than what came from the factory. You get the benefit just from installing new parts and ensuring the related adjustment is correct. You also realize a very noticeable improvement in overall vehicle dynamic behavior. The harder rubber prevents the strut rod from moving as much when a load is applied. This minimizes variations in suspension geometry that degrade performance and, in extreme cases, can cause the vehicle to swerve to one side or even completely out of control. The harder rubber may transmit a bit more noise and vibration into the interior, but it won’t be very noticeable. Ride quality should also be minimally affected, if at all, due to the way the loads are transmitted to the strut rods. When you consider the minor cost premium of the harder bushings versus the stock replacements, it’s an easy upgrade to make. Best of all, it looks just like the stock setup. A note of caution about using polyurethane bushings instead of rubber: While a little bit harder is better with the higher durometer rubber bushings, polyurethane can be too hard. The strut rods need to be able to pivot freely and the harder polyurethane bushings can restrict this movement. This can lead to the struts rods actually breaking, usually right where

An example of where the factory design can use some improvement is shock towers in the front suspension. Cracks commonly develop in this area due to normal wear and tear. The more aggressively the car has been used and/or the more inclement weather it has been exposed to, the more likely this problem exists.

If you’re not concerned about retaining a completely stock appearance and you don’t mind a bit more noise and vibration while you drive, you can go even further than the harder rubber strut rod bushings. You can eliminate the rubber bushings altogether and replace them with a design that relies on precisely indexed rod ends instead. These rod ends have virtually no compliance so they virtually eliminate any unwanted movement of the strut rods. We chose a Global West Suspension design because it used a Teflon-lined rod end for reduced noise and vibration (though still a bit more than with rubber bushings) and because it also had an additional adjustment sleeve to help get the proper alignment settings. If you go with this type of design, you must ensure the rod end is properly aligned with the control arm and strut rod, otherwise you might risk binding or even bending/breakage. The parts from Global are designed to index to the pocket and can only be installed in the proper orientation. This type of setup is pretty much mandatory if you intend to do any vintage road racing with your early Mustang; it improves the overall handling performance and is also much more able to withstand the abuse compared to a setup that retains rubber bushings. There’s a bit of tradeoff in vibration but the gains in handling, precision, and control under braking are well worth it if you don’t mind the different look. Most people will never even know it’s there since you have to get pretty low to the ground to even see these. These are worth considering for a higher-performance street car.

Similarly, the basic body structure of early Mustangs was not very rigid, especially by today’s standards. Over time the body structure tends to increasingly flex under load, producing unwanted noise and reduced effectiveness of the suspension, brakes, and steering. For our vehicle we decided to implement a few modifications to minimize body flex. These include additional welding in the shock tower area, installing welded-in subframe connectors, plus the use of an adjustable Monte Carlo bar and an aftermarket export brace.

Written by Frank Bohanan and Republished with Permission of CarTech Inc

GET A DEAL ON THIS BOOK!

If you liked this article you will LOVE the full book. Click the button below and we will send you an exclusive deal on this book.