Category: Restoration

Body Mounts. The parts manual shows three different “spacers” or more accurately, washers (Fig. 196. Items 6 & 11), used underneath the lower body mount cushions.

Of these, there are several NSNs. For the Front LH side, it is 5310-01-476-9321 [5310014769321], which also carries P/N 12339248-3. The Front RH and the rear use 5310-01-252-7285  [5310012527285] (12339248-2). The intermediate mounts (the ones in the middle) call out 5365-01-214-4987 [5365012144987 5583215].

Other than the front left hand side (the most difficult mount to deal with because it bottoms onto the frame and can only handle a maximum diameter washer), we can find no reason for use of different washers at the different locations.

First, it is unclear what purpose these washers serve. We speculate that it is either to 1) spread the load across the metal portion of the lower mount; or 2) (in event of catastrophic mount failure), it would prevent the body from separating from the frame.  There could also be some other reason we simply don’t know, but we have never seen washers used in this way for automotive purposes.

To be clear, we are not discussing the spacers used between the body and the upper mount to provide armor clearance on later versions.

After ordering all of the proper washers, two were on backorder status and we were only able to obtain two washers used for the front LH application, 12339248-3. (We like to keep extra parts in stock). This washer measured out at 5/8″ x 2 3/4″ x .250″. 

Having only the LH washer/spacers, they measured at 5/8″ x 2 3/4″ x .250. The front LH definitely has a clearance issue, as that is the single mount with a “bucket” welded over the frame.  

Comparing this washer to the lower months, it still covers the bulk of the metal on the largest mount, the intermediate mount 5342-01-186-7236 [5342011867236]  (12339247-3).

Upon determining that the smaller diameter washer appears to also work in the other positions, and being unable to timely source the washers/spacers called out for the right front, intermediate and rear positions, we determined that a washer of 3″ diameter will both fit and service properly.

We will use the extra front LH washer in the front RH location, and ordered four 5/8″ x 3″ x .250″ washers to be plasma-cut by my brother, David Grundman. As the washer 5310-01-476-9321 [5310014769321] we do have appears to be galvanized, we will be powder coating the plasma-cut washers for corrosion protection.

We will update this posting should we find any issues with using the washers in the positions as described above. If anyone has any insight as to why different washers are utilized, we would appreciate hearing from you.

According to the Parts Manual, a rivet is to be installed into the upper weep hole of the water pump. (Fig 31, Item 6).

This rivet is 5320-01-218-0721 [5320012180721], and is described as RIVET, SOLID 1/4 X 1/2.  This rivet is visible on the water pump we removed from the 6.5 NA. (between the coolant bypass fitting and the heater hose fitting).

Our replacement water pump, as installed, did not have this rivet.

We removed the rivet from the original water pump by prying it out with a screwdriver. It appears that the rivet was held in (or glued in) using Loctite 518 or similar. (“grape jelly”).  We noted that the 518 had not set up, either because the engine had not run enough to heat up, or it was simply the wrong material to use.

After removing the rivet, we installed it in our water pump using Permatex No. 2, which does harden up with air, but remains pliable. Although No. 2 has falled into disfavor over the years in place of materials such as RTV and pressure hardening sealants such as Loctite 518, we still find No. 2 suitable (and in some cases, superior) to modern sealants, and especially in this application.

We are unsure of the precise reason as to why the call out requires a rivet to be installed into the water pump. And this may explain the price discrepancy between interchange water pumps and OEM water pumps.  In our opinion, moving the rivet from the old pump to the new one (or even buying a new rivet) makes for a considerably less expensive replacement.

I consulted with Tim Grundman of Big Dawg Diesel Worx, LLC, and he informed me that he had never seen a weep hole plugged with a rivet on any industrial or agricultural applications.  And although this particular powerplant had not come from a vehicle with the fording upgrades, we speculate that the purpose of plugging the upper weep hole is to prevent contaminants from entering the weep hole and affecting the outer seal on the water pump bearing.

According to our research, this base water pump was used on a number of applications other than the 6.2 and 6.5 diesels. Likely there may have been an application where the water pump mounted upside down from this application, allowing the weep hole to show leakage regardless of position.

Further, it may be that under fording applications, plugging this hole prevents waterborne foreign material from lodging into the front of the water pump and aggravating seal damage.

Regardless of the reason, replacement or purchase and installation of a rivet will keep this water pump as factory designed.