Couplemate Trailer Parts
Couplemate Trailer Parts

Caravanning problems caused by stretching u-bolts can usually be easily fixed, however, unforeseen issues can have disastrous consequences.

A good example of a caravanning problem is the humble u bolt that clamps the spring to the axle. The bond between the spring and the axle prevents catastrophic events at high speed.

Therefore, it is of utmost importance the connection between spring and axle is inspected with an expert eye during servicing.

For example, the image below looks like there is something wrong. If you cannot pick the problem, I will help you identify the issues with comments under the photo.

Do you think the service mechanic noticed the nail or screw in the centre tyre?

Basic Observations

  • Triaxle Configuration.
  • 60mm Round 2t axle
  • 12″ Electric Backing Plates
  • 60mm Rocker Roller Springs
  • Weight difficult to ascertain due to variable leaf spring configuration.

What is wrong

  1. Leaf separation between leaf 2 and 3 indicates loose u bolts.
  2. Separation confirmed when looking between axle pad and axle.


Did you notice the spanner on the ground and not a rattle gun!

Clever caravan and camper trailer service mechanics do not use rattle guns on ubolts. Although, powerful battery rattle guns available, in this instance a spanner is the most effective piece of equipment..

Rattle guns create heat causing the nylon inside the nylock to burn and become ineffective.

Steps and tips

  • Surprisingly the stretched u bolts on this rig above will be OK.
  • Replace the nylock nuts.
  • Retighten the u-bolts in a diagonal rotation until the fishplate starts to bend.
  • Following these steps and your caravanning problems with u bolts are resolved until the next service.

If you are unsure about checking these u-bolts, call your service technician to make a service booking before your next trip. It may just save your life.

Finally, one further point. Notice the spring wrap from the main image above?

The spring wrap has opened a little. This is caused by the spring warping during reversing.

Tight u-bolts play a critical role in preventing spring warp. Tight u-bolts will prevent these spring wraps from opening.

Always mention u-bolt tightening check to your service mechanic during your caravan service events and watch these critical caravanning problems disappear.

There is also a very good u-bolt article here.

Couplemate U-Bolts

Round U-Bolts


Square U-Bolts





Part Number
1 ½” (39mm)½” (13mm)4″ (100mm)U39R4GH
1 ½” (39mm)½” (13mm)4½” (112mm)U39R45GH
1 ½” (39mm)½” (13mm)5″ (125mm)U39R5GH
1 ½” (39mm)½” (13mm)5½” (137mm)U39R55GH
1 ¾” (45mm)½” (13mm)4″ (100mm)U45R4GH
1 ¾” (45mm)½” (13mm)4½” (112mm)U45R45GH
1 ¾” (45mm)½” (13mm)5″ (125mm)U45R5GH
1 ¾” (45mm)½” (13mm)5½” (137mm)U45R55GH
1 ¾” (45mm)½” (13mm)6″ (150mm)U45R6GH
1 ¾” (45mm)½” (13mm)6½”(162mm)U45R65GH
2″ (50mm)½” (13mm)4″ (100mm)U50R4GH
2″ (50mm)½” (13mm)4½” (112mm)U50R45GH
2″ (50mm)½” (13mm)5″ (125mm)U50R5GH
2″ (50mm)½” (13mm)5½” (137mm)U50R55GH
2″ (50mm)½” (13mm)6″ (150mm)U50R6GH
2″ (50mm)½” (13mm)6½”(162mm)U50R65GH
2″ (50mm)½” (13mm)7″ (175mm)U50R7GH
2 ⅓” (60mm)½” (13mm)5″ (125mm)U60R5GH
2 ⅓” (60mm)½” (13mm)6″ (150mm)U60R6GH
2 ⅓” (60mm)½” (13mm)7″ (175mm)U60R7GH
2 ½” (65mm)½” (13mm)5″ (125mm)U65R5GH
2 ½” (65mm)½” (13mm)6″ (150mm)U65R6GH
2 ½” (65mm)½” (13mm)7″ (175mm)U65R7GH
1 ½” (40mm)½” (13mm)4″ (100mm)U40S4GH
1 ½” (40mm)½” (13mm)4½” (112mm)U40S45GH
1 ½” (40mm)½” (13mm)5″ (125mm)U40S5GH
1 ½” (40mm)½” (13mm)5½” (137mm)U40S55GH
1 ½” (40mm)½” (13mm)6″ (150mm)U40S6GH
1 ¾” (45mm)½” (13mm)4″ (100mm)U45S4GH
1 ¾” (45mm)½” (13mm)4½” (112mm)U45S45GH
1 ¾” (45mm)½” (13mm)5″ (125mm)U45S5GH
1 ¾” (45mm)½” (13mm)5½” (137mm)U45S55GH
1 ¾” (45mm)½” (13mm)6″ (150mm)U45S6GH
1 ¾” (45mm)½” (13mm)6½”(165mm)U45S65GH
1 ¾” (45mm)½” (13mm)7″ (175mm)U45S7GH
2″ (50mm)½” (13mm)3″ (75mm)U50S3GH
2″ (50mm)½” (13mm)4″ (100mm)U50S4GH
2″ (50mm)½” (13mm)4½” (112mm)U50S45GH
2″ (50mm)½” (13mm)5″ (125mm)U50S5GH
2″ (50mm)½” (13mm)5½” (137mm)U50S55GH
2″ (50mm)½” (13mm)6″ (150mm)U50S6GH
2″ (50mm)½” (13mm)6½”(165mm)U50S65GH
2″ (50mm)½” (13mm)7″ (175mm)U50S7GH
2″ (50mm)½” (13mm)8″ (200mm)U50S8GH
2″ (50mm)½” (13mm)10″ (250mm)U50S10GH
2 ¼” (56mm)½” (13mm)4½” (112mm)U56S45GH
2 ¼” (56mm)½” (13mm)5″ (125mm)U56S5GH
2 ¼” (56mm)½” (13mm)5½” (137mm)U56S55GH
2 ¼” (56mm)½” (13mm)6½”(165mm)U56S65GH
3″ (75mm)½” (13mm)3″ (75mm)U75S75GH
3″ (75mm)½” (13mm)4″ (100mm)U75S100GH
3″ (75mm)½” (13mm)5″ (125mm)U75S125GH
3″ (75mm)½” (13mm)6″ (150mm)U75S150GH
3″ (75mm)½” (13mm)7″ (175mm)U75S175GH
3 ¼” (82mm)½” (13mm)4 ¾” (120mm)U80S120GH
4″ (100mm)½” (13mm)3″ (75mm)U100S75GH
4″ (100mm)½” (13mm)4″ (100mm)U100S100GH
4″ (100mm)½” (13mm)5″ (125mm)U100S125GH
4″ (100mm)½” (13mm)8″ (200mm)U100S200GH
1 ¾” (45mm)⅝” (16mm)6″ (150mm)CM600GH
2″ (50mm)⅝” (16mm)6″ (150mm)CM602GH
2 ⅓” (60mm)⅝” (16mm)7″ (175mm)CM604GH
1 ¾” (45mm)⅝” (16mm)6″ (150mm)CM601GH
2″ (50mm)⅝” (16mm)7″ (175mm)CM603-7GH

© Steve Wotherspoon 28th June 2019

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