Care, Maintenance and Lubrication of your fifth wheel

It goes without saying that if your fifth wheel fails for any reason then it’s going to cost you time and therefore money. With D’Angelo fifth wheels we’ve tried to make maintenance as easy as possible, but there are still many things you, the operator, can do to make sure that the fifth wheel is working optimally.

Essentially there are two areas that you the operator can check: is the fifth wheel still hitching correctly and is the fifth wheel lubricated well.

1. Testing the jaw
This test requires someone to watch the top plate of the fifth wheel as another person hitches to a trailer and then moves the truck slowly backwards and forwards with the trailer brakes applied. The person watching the top plate is looking for any movement of the top plate relative to the trailer only. If there is movement then indeed the jaws could worn or loose.
    D’Angelo fifth wheels all have jaw adjustment bolts located at the rear or side of the unit depending on the model (see below). Using the correct tool the jaw can be adjusted easily, however it is best to have this done by a professional.

CAUTION: incorrect adjustment can result in excess pressure on the kingpin making un-hitching difficult or impossible – and at worst catastrophic jaw failure. If you are in any doubt how to correctly adjust the jaw please call either one of D’Angelo’s representatives on 03 9369 0633 or drop into our Laverton North workshop and we’ll assist you in the process.

Adjusting the MiniMax jawAdjusting Maxi jaw
  MiniMax adjustment bolt                        Maxi 50/HD/Mini 50 adjustment bolt

If your jaw still remains loose then it may be the case that repair or reconditioning might be suitable rather than a direct replacement. DO NOT use the fifth wheel for trailer pulling or be tempted to over-tighten the adjustment bolt, but bring your truck into our workshops and our engineers will give you advice on how to proceed.

2. External examination of the fifth wheel
Any examination of a fifth wheel should begin with a good clean; use a steam-cleaner if you have one and clean off the top plate, casework, pedestals and the assembly if present. Once the fifth wheel is clean you can take a proper look (you may need a torch to examine the jaw area).

Dirty fifth wheel
In need of a clean! Does your fifth wheel look like this?

Loose jaw pins: D’Angelo fifth wheels only have one pin for the jaw mechanism. It should be tight, and the surrounding grease, if visible, should be crack-free. Cracking in the grease around the pin indicates that it is loose; if this is the case the fifth wheel should be brought into our workshop for attention.

Fifth wheel jaw pin location

Dents and wear on the top plate: Accidents do happen and severe damage to the top plate can also result in distortion of the fifth wheel chassis. This in turn can affect the effectiveness of the several precise mechanisms within the casework, including the jaw action and therefore your ability to safely lock them. If you think there is significant damage to the top plate D’Angelo can quickly give a professional opinion and if necessary test the unit.
    By laying a straight edge across the fifth wheel wear spots can be identified which might have been caused by a trailer with a problem with its skidplate or kingpin. These wear spots can cause uneven loading of the top plate and unusual forces through the mechanisms which in turn might result in premature failure in the unit. If you suspect that wear might be a problem with your turntable, a quick visit to our workshop will give you piece of mind – and might well save you a heap of money.

Damaged levers and handles: If you, or another driver, have bent or in other ways damaged handles or levers on the fifth wheel then you are not the first! Handle damage is fairly common and if the part is not repairable then we hold a wide range of handles in stock and can of course replace them for you. By bringing the truck to our workshop we can easily identify the required part and we can also check that other internal problems have not occurred, or may occur at a later date.

CAUTION: Fifth wheels contain several mechanisms, some with heavy duty springs attached. If you are unsure, or not qualified for this type of maintenance, then it might be very wise to get professional assistance, bad injuries to hands and arms are not unheard of.

Stress cracking of components: The fifth wheel and its components have several tens of thousands of Newtons of force imposed on them regularly, which is why it is important to keep everything in top condition (10000N = 1t under gravity). However, in the unlikely occasion that things do go wrong, you might be able to spot problems before they result in component fracture and dropped trailers or worse. Check all visible components for fine cracks, and pay special attention to weld-lines around the top plate and if your pedestals are welded to the mounting assembly, check those too. Do not forget to oscillate your fifth wheel so you get a good look from all directions. This close visual inspection should also highlight if any parts are missing, loose or badly damaged.

Nuts and Bolts: It seems obvious, but by making sure all the relevant nuts and bolts on your fifth wheel and assembly are tight, the rewards will be great. You might find the D’Angelo Lug Indicator useful for showing you when the foot-pin bolt has either moved or been tampered with.

3. Worn Bushes
Testing for worn bushes is an easy procedure. Using a crowbar or prybar, gently try lift the fifth wheel vertically from one of the side edges near the pedestal. There should be no significant movement as the heavy duty rubber bushes are required to be tight around the footpin. If you can see your fifth wheel's footpin nut moving relative to the pedestal then the bushes are likely to need replacing, which is a routine service for D'Angelo's engineers.

4. Lubrication
Once you have checked your fifth wheel it’s time to lubricate the required areas. Firstly, if you have D’Angelo greaseless pads on your fifth wheel (made from a tough, low friction plastic) you do not need to grease the top plate! For other configurations you’ll need to draw a small bead (6mm or ¼”) sparingly across both sides of the top plate. Remember that ideally the skidplate and top plate will be very close together, so any excess grease will just be waste, and create unnecessary mess!    
   The jaw mechanism needs a little lubrication too, just go around the surfaces that will be in contact with the kingpin with a smallish bead (6mm or ¼”).

Lubrication of fifth wheel jaw

    In addition, some of D’Angelo’s fifth wheels have a grease nipple located on the underside of the rear of the fifth wheel. Oscillate the top plate as far forward as it will go and introduce a squeeze of grease into the nipple if one is present.
Grease point under fifth wheel
    There are several grades of grease available and D’Angelo stock many of the best performing, but which also offer the best value (see more detail here). A quick call to D’Angelo will allow our sales team to advise on which is most suited for your application.

Lubrication intervals: As far a lubrication intervals go, the rule of thumb is the more you hitch and un-hitch the more you'll need to keep an eye on the fifth wheel and its lubrication topped up. The hitching procedure is more likely to introduce dirt and remove protective grease than normal medium/long haul work.



Contact D'Angelo

D'Angelo Engineering are based in Laverton North, Victoria and are close to both Tullamarine and Avalon airports. Laverton North is also easily reached from the Western Ring Road and Princes Freeway.

Phone: +61 (0) 3 9369 0633
Fax: +61 (0) 3 9369 4717

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