Please read the information below, it may help you. Further information may be available on the manufacturers websites; Orlandi has 3d videos showing how easy it is to carry out repairs on their draw bar couplings; WAP has much more in their range than we list, however it is all available to order; if you cannot find the answer to your query here, please contact us

F.A.Q. & Technical Help

Drawbar CouplingsComplimentary Kits5th WheelsTrailer EyesUnder Run Bars/Tow BarsTFS Trailer SteeringDraw Beams/Drop PlatesDraw BarsLight AxlesLanding Legs/Turntables

FAQ (Couplings & eyes)


1. Do your eyes fit other makes of coupling? yes, absolutely, all of our eyes are guaranteed to be universal, there is NO difference in use.

2. Do your eyes come with a bush? yes, all of our eyes come with the bush fitted, ready for use.

3. Are bolts included with the eyes? No, because some builders want to use their own bolts, but we can supply them separately.

4. Do I need new bolts with my eye? yes, it is recommended not to re-use the eye bolts, as it is a safety item.

5. My 50mm eye bolt kit (RO00035) has 2 bolts longer than the others, why? These 5mm longer bolts are to go through the 2 special wedge shaped washers on the two un machined holes.


6. Can we replace another brand of coupling with yours? Yes, all of our couplings are interchangeable with our competitors products, just check the mounting hole spacing.

7. is your coupling “load bearing/suitable for”? Yes, we don’t bother with lots of different models, our in stock 40/50/57mm couplings are all highest rated and multi purpose. why fit a lesser coupling, fit the top model and you know it can do it all.

8. How can I tell which coupling I have? For most parts we only need to know the pin size, (40,50,57mm etc) and if it is air or manual operation.

9. Do I need to be specially qualified to repair your couplings? No, any competent mechanic is more than capable to service or repair our couplings.

10. Do I need any special tools to service or repair your couplings?  No, all of our couplings are built with normal tools in mind, any normal truck workshop should have everything that is required.

11. Can I buy individual parts for the coupling?   Yes, there is no need to buy a complete mechanism if you just need a pin! All of our couplings are fully repairable, with most parts available either separately or in convenient kits.

12. Which type of air operation do I have?  Some older couplings may have a silver cylinder type air actuator (with linkage) this is an A9 or H9 , all newer types will have a yellow Kinitrol air motor (direct drive) this is an A7. (for current version parts, please visit the “complimentary kits” pages)

13. Is my older air cylinder version an “A9” or “H9”?  if the cylinder mounting plate and protection plate are 1 piece, it is an “A9”. If it is possible to remove the protection plate and leave the cylinder in place it is an “H9”. (please see parts lists for previous models below for spares)

old air kit CO001400 50mm A7 (not for current model)

old air kit co002000 50mm 57mm A9

old air kit CO02100 50mm 57mm H9

14.  Can you help diagnose an air problem?   Please refer to the diagrams and fault finding links below;

Air system fault finding guide

co1400_man web me  for 50mm couplings

co1420_man web me  for 57mm couplings

15. Can you help diagnose an electrical problem?   Please refer to the wiring diagrams and fault finding links below;


Proximity Sensor Testing CO016

 16.  Can I get parts for my old GX57 coupling?   yes,  please see parts list below;

GX57 parts

17. Can I get parts for my old UN766 coupling?  yes, please see parts list below;


18.  Can I get parts for my old E509 coupling?  yes, please see parts list below;


19. The nut does not line up with the split pin hole on the main shaft on my new coupling, why?  If E575, check the correct shims have been used (5 x 6mm on a WAP beam), and that the mounting assembly has been lubricated, including the rubbers




FAQ (5th Wheels)

1. Can we replace a different make of 5th wheel with yours?  Yes, if it has an ISO foot, they are interchangeable. Just check the top plate height.

2. Can we swop your top plate onto a slider without feet? No, unfortunately our top plates do not fit the type of slider that has an integrated top plate.

3. Can I buy individual parts for the 5th wheel? All of our 5th wheels are repairable, with most parts available either separately or in convenient kits.

4. Can we add the grease free inserts to our current 5th wheel? No, only 5th wheels designed to be grease free can use them.

5. Does the 5th wheel or slider come with the mounting bolts? No, not unless specified, this is because there are many options depending on the chassis type, the manufacturers recommendations should always be followed.

6. I need to fit the 5th wheel further up the chassis than normal, but this is beyond the mounting points, how can I?  We can provide mounting extensions for some chassis types.

7. Can I change my 3.5” 5th wheel into a 2” 5th wheel?  Yes, the RP90 is the same basic 5th wheel, we do kits to change the 2” into 3.5” and 3.5” to 2”.

FAQ (Under run bars/Tow bars)

1. Can I cut down the mounting brackets?  Yes you can trim off excess from the top of the mountings.

2. Can I change the types of bolts and bolt pattern to mount it?  Yes, but please ask for confirmation, we can give written permission to vary the fitting instructions as long as it is agreed by WAP in advance.

3. Is it approved to fit my chassis?  Yes, all of our under run bars and tow bars are universal. They can be fitted to any chassis.

4. Is it approved to go on a 5t or 44t truck?  Yes, most of our under runs and tow bars are good for 3.5t to unlimited.

5. Can I fit it to a trailer? Yes, our bars are both N and O approved.

6. Can I tow 3.5t trailer on a 32t truck?  Yes, our tow bars and couplings are rated at 31kN,

7. What type of tow ball/pin can I fit?  The tow bars are double drilled to accept either a 90mm two bolt fitting, or a four bolt euro fitting. Both options have multiple heights on the mounting.

8. Can you supply a suitable coupling?  Yes, we stock a huge range of options, most popular is the 31kN rated ball and pin coupling.

9. Are they in stock?  usually yes, most of our bars are available from our UK stock.

10. What is the standard finish? The default finish is black KTL (electroplate) on most bars, (SG2012 is powder coated white)

11. Can I galvanise it?  Yes, you can, but all WAP under run bars and tow bars can be ordered with the option of being fully hot galvanised, most from our UK stock.

12. Does it come pre drilled for my chassis?  Not from our stock, but all of them can be ordered in from the factory pre drilled and trimmed to your pattern, ready to bolt on, in black or hot galvanised.

13. what about the new R58 regulations revision 3, from September 2019? we are developing a whole new RUPD system, the first new rev 3 fully approved under run bar and tow bar will be available from September 2018, with new models being added through the year. please enquire if you have any special requirements you would like us to consider