Why do leaf springs squeak?

April 14, 2020
Rear leaf springs in most trucks are made of several leaves. When the spring flexes, leaves move against each other and this can cause squeaking. To reduce rubbing between the leaves, the spacers (silencer pads or anti-friction pads) are typically installed between the leaves, see the photo.
Leaf spring Leaf spring in the GMC pickup truck.
What are the common problems that cause squeaking?
  • Debris, small rocks stuck between the leaves
  • Worn-out spacers
  • Leaf spring rubs against one of the rebound clips
  • Squeaky leaf spring bushings
In many cases, squeaking is caused by the debris caught between the spring leaves; often squeaking starts after driving on unpaved or muddy roads. If you check 4x4 forums, many truck owners advise pressure washing the leaf springs after mudding or driving on an unpaved road. Do car manufacturers recommend cleaning leaf springs?
Some car makers don't mention it, but, some do. For example, the owner's manual for the 2013 Ford Super Duty says:
Rear suspension components may require regular cleaning with a power washer or a thorough rinse with a strong stream of water if the vehicle is operated in dusty or muddy environments.
We also found GM service bulletin 06-03-09-004M for the 1999-2007 Chevrolet Silverado and a number of other trucks about a squeaking noise from the rear of the vehicle. Here is the link to the bulletin on the NHTSA website. The bulletin recommends first pressure-washing the leaf springs to clean the dirt, then drying the springs with compressed air, then greasing the inserts (spacers) with a special lubricant. Judging by the part number of the lubricant provided in the bulletin, it's the Molykote ™ M77 paste. However, the bulletin warns that it's a temporary measure and periodic cleaning and re-applying grease may be necessary throughout the life of the vehicle. Many truck enthusiasts recommend not to use any grease on leaf springs, but in this case, we will take the manufacturer's (GM) recommendations. We also found the service bulletin NTB18-003 for the 2004-2015 Nissan Titan. The bulletin instructs cleaning the working surface of the rear leaf spring tip inserts (spacers) to solve the noise concerns.
It's worth noting that the fact that there is a service bulletin doesn't mean that the problem is covered under warranty.

Another common problem that often causes squeaking is when the inter-leaf spacers wear out allowing metal to metal contact between the leaves, see the photo.
Leaf spring wear In this truck, squeaking was caused by a worn-out spacer that allowed metal-to-metal contact. See another illustration Fig 2.
If a spacer is worn out or missing, the lower leaf grinds into the leaf above. For that reason, it's a good idea to replace inter-leaf spacers if they look worn out; parts are not very expensive ($15-$30 for a kit). For example, Toyota service bulletin T-SB-0273-17 for the 2016-2017 Toyota Tacoma recommends cleaning and removing grease and dirt between the leaf springs and replacing silencer pads (spacers). Here is the link to the bulletin. The bulletin, though, warns against using any grease on the pad and spring surface. The bulletin also provides instructions for mechanics on how to find the the source of the noise.
One more possible source of squeaking noise is the contact area between the leaf spring and the inner edges of the rebound (wind-up) clip; marked in the photo.
Leaf spring Leaf spring in the GMC pickup truck.
For example, Nissan service bulletin RA05-003 for the 2005-2006 Nissan Frontier instructs mechanics to inspect the inside of the rear leaf spring wind-up clip plastic cover for contact (rubbing) with the leaf spring. If there are signs of rubbing, the bulletin advises applying grease (Molykote 7 ™) between the leaf spring and wind-up clip plastic cover. For a similar concern, the bulletin RA05-002a for the 2004-2006 Nissan Titan advises replacing the leaf spring wind-up clip cover if signs of rubbing are present.

Leaf spring shackle Squeaky leaf spring and shackle bushings are common.
Worn leaf spring bushings as well as shackle bushings are known to cause squeaking noises too. Parts are not expensive, but replacing leaf spring bushings involves a considerable amount of labor. in most cases, the leaf springs will need to be removed, although some mechanics can do the job with leaf springs in place. In many trucks new bushings will need to be pressed in. There are plenty of YouTube videos on how to do it.