Moog Overrun Damper for PEITZ/BPW PAV/SR 2.0 Overrun Coupling - 235 mm Shock Absorber, 12 mm Eye, 8 mm Clamping Sleeve Mount, for Trailers up to 2000 kg

The Moog overrun damper is a replacement part for the PEITZ/BPW PAV/SR 2.0 overrun coupling, the braked drawbar head used on caravans, light utility trailers and car transporters with a gross weight of up to 2000 kg. The damper, also called an overrun shock absorber, works inside the housing of the overrun coupling and controls the movement of the drawbar. When the car brakes, the trailer pushes against the tow ball, the drawbar slides into the housing and applies the trailer wheel brakes. The damper slows this movement down, so the trailer brakes come on smoothly, without jerks and knocks every time you lift off the accelerator. This version has an eye to eye length of 235 mm, a 24 mm cylinder, a 12 mm eye at one end and a mount for an 8 mm clamping sleeve at the other. The part measures 235 x 24 x 26 mm and has a net weight of 250 g. The pack contains one black damper. Fixing parts such as the bolt or the clamping sleeve are not included, so check their condition when you replace the damper and have new ones ready if needed.

Key features

• replacement part for the PEITZ/BPW PAV/SR 2.0 overrun coupling
• for trailers with a gross weight of up to 2000 kg
• 235 mm eye to eye (short version, without X)
• 24 mm cylinder diameter
• mounting: 12 mm eye and 8 mm clamping sleeve mount
• dimensions 235 x 24 x 26 mm
• colour black
• net weight 250 g
• manufacturer part number 73.822-00
• contents: 1 piece

How an overrun damper works

An overrun brake has no power supply and no brake lines of its own. The trailer generates the braking force itself: when the car slows down, the trailer pushes against the tow ball through its inertia, the drawbar slides into the housing of the overrun coupling, and a system of levers and cables applies the brake shoes in the wheels. Without a damper, the drawbar would move abruptly with every change in speed and the trailer would knock against the tow ball when braking and when you lift off the accelerator. The overrun damper works like a shock absorber: it resists fast movement of the drawbar, so trailer braking builds up gradually, and short changes in speed, for example on bumpy roads, do not apply the brakes. A working damper improves the stability of the car and trailer when braking and protects the parts of the overrun coupling from impacts.

Which overrun couplings it fits

• The damper is designed for the PEITZ/BPW PAV/SR 2.0 overrun coupling, used on trailers with a gross weight of up to 2000 kg.
• It fits the short versions of this coupling, which use a damper with an eye to eye length of 235 mm.
• Versions marked with the letter X (for example MX or EX) have a longer stroke and need a damper of approx. 335 mm eye to eye, so this part does not fit them.
• PAV/SR 1.3 and PAV/SR 2.7 couplings have their own dampers with different damping characteristics, even if the length is similar.
• BPW ZAF, AL-KO and KNOTT couplings need other dampers, which you will find in the related products section.

How to check that this is the right part

• Read the type plate on the housing of the overrun coupling. It should show the type PAV/SR 2.0 and the version.
• If the plate cannot be read, measure the old damper. The distance between the centres of the mounting holes when extended should be approx. 235 mm.
• Check the cylinder diameter, which is 24 mm on this version.
• Compare the ends: a 12 mm eye at one end and a mount for an 8 mm clamping sleeve at the other.

Signs of a worn damper

• The trailer jerks and knocks against the tow ball when braking or when you lift off the accelerator.
• The trailer brakes come on unevenly, suddenly or when the car has barely slowed down.
• With the trailer uncoupled, you can push the drawbar in by hand without clear, even resistance.
• There are oil traces, corrosion or mechanical damage on the cylinder or piston rod.
• A failed damper does not change the braking force itself, but it makes the trailer brakes work abruptly and wear faster. Replace it at the first signs.

Step-by-step replacement

• Park the trailer on level, firm ground, chock the wheels and uncouple it from the car.
• Support the drawbar with the jockey wheel or a stable stand so the trailer cannot tip.
• Remove or slide back the protective bellows of the drawbar to get access to the inside of the overrun coupling.
• Remove the fixings at both ends of the old damper: the bolt or pin in the 12 mm eye and the clamping sleeve in the 8 mm mount. Drive the sleeve out with a suitable pin punch.
• Take out the old damper and clean dirt and rust off the mounting points.
• Fit the new damper in the same position as the old one and secure both ends. Replace a damaged or worn clamping sleeve with a new one.
• Push the drawbar in and out a few times to check that it moves with even resistance and nothing rubs.
• Refit the protective bellows and check that it seals well at both ends.
• After the replacement, check the trailer brake adjustment according to the instructions of the overrun coupling and axle manufacturer. If you have no experience with trailer brake systems, have a workshop do the job.

Inspection and care

• Check the damper at every trailer service, ideally once a year or before a longer trip.
• Keep the protective bellows in good condition. A cracked bellows lets water, sand and road salt into the coupling, which damage the piston rod and the damper seal.
• Do not paint the piston rod or apply grease to it, as dirt sticks to the surface and wears the seal faster.
• Do not heat the damper or weld near it without removing it first.

Other Moog overrun dampers

• Moog overrun damper for AL-KO 200 V - 12 mm eye, 10 mm thread
• Moog overrun damper for KNOTT KF 7.5 - 12 mm eye, 10 mm thread
• Moog overrun damper for PEITZ/BPW ZAF 1.5-2 - eye and eye

Technical data

Manufacturer

moog TRAILERPARTS GmbH, Junkersstraße 3, 68519 Viernheim, Germany.