Five Most Neglected Maintenance Areas in Your Pantera

Last Updated 04/17/07

The Five Most Neglected Maintenance Areas in Your Pantera

by Jack DeRyke

Published April 2002 in the POCA Newsletter

The Five Most Neglected Maintenance Areas In Your Pantera

Over the years, I've noticed that, while the DeTomaso Pantera continues to be THE most-modified sports car in history, it also is sinfully neglected as far as down-'n-dirty maintenance in certain areas. Nearly everyone knows of the rear wheel bearing/axle shaft size mismatch, the loss of steering rack lubricant causing the single steering bushing to wear out, and a few others. But the areas I list here are difficult to access, most are out of sight so are also out-of-mind, and quite a few owners probably don't even know that they could vastly prolong their car's operating life by doing some "extra" routine maintenance.

1) Lubrication of the lower rear pivot shafts in the rear suspension.
The design of your Pantera rear suspension doesn't use lower rear ball joints; it uses a nearly foot-long pivot shaft that passes through the lower rear a-arm ends and through the lower part of the rear axle uprights. The shaft rides on two plain bushings at each end of the carrier. There is no external way to lube the a-arm pivot points or the brass carrier bushings.

To make matters worse, there is an anti-crush sleeve inside the cast-iron carrier that is made of hardened steel. This type of steel rusts very easily, and without copious amounts of grease, soon corrosion-welds itself to the pivot shaft. When this happens, the assembly cannot be pressed apart but must be cut in pieces to disassemble. The problem is so prevalent, some vendors have kits made up to replace the parts you will destroy in disassembling this critical area of your rear suspension.

If you're lucky enough to get yours apart, the assembly can be lubricated by hand: both a-arm pivots and both bushings. There are also kits that substitute a gun-drilled pivot shaft with a grease fitting on one end. There are crosswise drillings in the pivot shaft that connect to the carrier bushings and a-arm pivots. Some owners have added extra grease fittings to the carrier that accomplish much the same task.

2) The effort reduction linkage under the dash
(L models only) is composed of numerous pivots, links and shafts, all unbushed steel-on-steel, that were probably never lubricated during your Pantera's construction in Italy. Now, thirty years later, most parts will be either worn or loose, or frozen solid. Both contribute to reducing the release distance your clutch linkage can produce, this causing more wear on your ZF's very expensive gear synchronizers. Unfortunately, due to the way the mechanism is designed, one almost needs to remove the dashboard in order to remove and repair any worn links. Damaged holes in the links can be welded up, re-drilled and reamed to size for tiny bushings. Undamaged parts can be greased and reassembled for the next decade's use.

3) The twin needle bearings on the ends of the clutch bellcrank shaft in your engine's bell housing.
These small bearings are well sealed and were lubed at the factory, but it's been thirty-plus years ago since that was done. I guess they were not designed to be serviced, because to re-grease them, one needs to pull the transaxle (or at least slide it back far enough to allow access to the inside of the bell housing. Two huge roll pins must be driven upward away from the bell housing as they're too long to clear things when driven in the "easy" direction - toward the bell housing.

Once the roll pins are out, the bellcrank can be driven sideways through the cast iron throw-out fork and out the right side of the bell housing. The slave cylinder lever need not be removed. Then, both needle bearings can be driven out, cleaned and checked, then hand-greased and re-inserted if still OK. I've never seen one that was utterly destroyed, but I have seen a few with flat-sided needles. The angle the shaft and bearings travel through is very limited, so only a few needles take all the load. A dedicated owner could add zerk fittings to the bell housing above these little bearings, and a pump of grease once in a while would surely not be bad.

4) The pilot bushing in the rear of the crankshaft.
I hear of guys resealing their ZF input shafts and changing throwout bearings, but seldom do they mention changing the pilot bushing. This plain, oil-impregnated bushing supports the nose of the transmission clutch-shaft, and wears out rather regularly. When it wears, the shaft can wobble, which not only causes clutch problems, but can also cause the ZF input shaft seal to fail.

There are three types of pilot bushings to common use: the stock one is sintered bronze, the second is sintered bronze adulterated with iron filings to make it cheaper, and the third is a small needle bearing. The iron/bronze bushing and needle bearing have both been known to wear the nose of the transmission when their supply of lube dries up. The cheap iron/bronze busing can be detected at your parts supplier with a magnet. To service the area requires the transmission and clutch to be removed, so it usually only is accessible during engine or clutch rebuilds.

The stock bushing can easily be removed simply by screwing a 3/4-thread tap into the bushing. Screw it right in until the tap bottoms on the crank, then continue tightening. The bushing will move backwards and out with little effort. Removing a defective needle bearing requires a dedicated bearing puller, or a small grinder, a hammer and chisel. A new pilot unit taps in with a hammer & the proper sized socket as a driver.

5) The stock sintered bronze fuel filters in Holley carburetors (Rochesters have tiny paper filters).
These filters are included with most 4bbls. Rochesters have a single paper cartridge. Holley dual-inlets have two sintered bronze. They are all behind the inlet nuts on the carbs. They are very good filters and catch a lot of trash from poor-quality gasoline as well as tank rust and debris from deteriorating hoses. Then they plug up, your carb goes lean and you have no power. To access them, the fuel inlet line(s) must come off, then the inlet nut(s). Don't lose the thin paper gasket under the fuel nut. The filter, if it's still there, will be spring-loaded and will pop out a bit.

Most guys throw them away, substituting a larger external filter. The small chrome & glass ones are subject to breakage of the glass cylinder and/or the brass shaft that holds the assembly together. The fuel flow capacity of these filters is really too low for a performance engine. Speed shops have racing units that will vastly outflow the small ones, have easily replaceable filter cartridges and basically pay for themselves in trouble not caused.

6) Check your U-joints for failures ready-to-happen.
This is pretty easy: when the U-joint needles begin to chip and flatten, they microweld and drag on the cap. So the cap base, visible through the halfshaft yoke holes, begins to rotate under its snap-ring. This rotation leaves a polished ring on the outside of the U-joint cap.

This is also a good argument for NOT using the show-car logo U-joint cap covers, or the chrome grease shields that encircle the inner U-joint. Another tip-off for about-to-fail U-joints is red dust built up around the neoprene seal between the cap & U-joint body. Wipe your finger around this area occasionally; any red dust visible is rust from destroyed needle bearings. When a U-joint fails in the Pantera, the spinning half-shaft is freed of restraint and flails around. Inner joint failure usually cracks the ZF cases; outer joints tend to bend the sheet metal your rear suspension is bolted to, and may manage to take out the brake line fitting on that corner. Both types of damage are very expensive to repair.

7) When's the last time you checked the coupling bolt connecting the steering shaft to the rack pinion?
To renew the steering rack bushing, the rack ideally will be removed. If in reassembling, the little 8mm bolt fastening the steering shaft-to-rack coupling loosens or snaps, the shaft and steering wheel can become disconnected from the rack, leaving you with no steering at all. This is obviously a rare condition, but I found a friend's "new-to-him" Pantera with exactly this problem. The critical bolt is high up on the left side of the front end, and will require you to turn the wheel so as to get the bolt at the right angle for your socket and long extension. Be careful - specified torque is 24 inch-pounds. Over-torquing the bolt will create exactly the scenario you are trying to avoid! This would be an excellent place for a couple of drops of red Lock-Tite before tightening.

8) Has your Pantera's 351C ever had its factory freeze plugs replaced?
If no, be aware that factory freeze plugs are mild steel, and unless all owners of the engine were as diligent as you(?) about changing antifreeze yearly, they are all badly corroded and probably on the verge of failure. Only one of the six can be practically accessed with the engine installed, just in case you figure it can be done anytime; two are under the motor mounts. Replacement plugs should be brass; there are low and high-side types. As far as sealing, it makes no difference which type is used. No sealant is normally needed, but coating the edges with RTV or Permatex can be done after installation, if the block is scarred from removal of the old plugs.

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