Changing the Rubber Jounce Stops in a Rota-Flex Pin Box

Updated 06/29/2018 | Published 06/27/2018

Question:

I own a Lippert 1621 pin box and the rubber cushions fell out. The box is only 3 years old and they say the parts are unavailable and because it’s 3 years old it’s not under warranty. I would hope to get more than 3 years for such an expensive pin box. It would be nice if I could get the replacement cushions and install myself. They say it requires a hydraulic press and the parts are obsolete. If I could get the dimensions and type of materials used I could probably continue using it. I’m a diesel mechanic and find this totally ridiculous to say it can’t be fixed.

asked by: Ronald B

Expert Reply:

I can tell you the procedure for replacing the jounce stops on the Rota-Flex pin box though the exact replacement parts are not available like you said. They are a rubber compound but the specifics of it I do not know.

1. With Long Needle-nose pliers, from the back of the pinbox, squeeze tag ends of Cotter Pin together and push it out of the Front Jounce Stop and it’s channel. Cotter Pin may need to be pulled out from the front of the pinbox to completely remove it from the Jounce Stop.
2. Repeat to remove second Cotter Pin.
3. Tap out Jounce Stop from its Channel.
4. From the front of the pinbox, repeat the procedure to remove Rear Jounce Stop Block.
5. Replace old Front Jounce Stop with new Jounce Stop.
6. Lubricate the Jounce Stop with Silicon spray and align holes in the new Jounce Stop to the holes in the Channel.
7. Tap new Jounce Stop in place with a dead blow hammer.
8. Replace Cotter Pins.
9. Remember to flare the tag ends of the Cotter Pins away from each other to hold Jounce Stop securely.
10. Repeat procedure to replace the Rear Jounce Stop.

Note: The new Jounce Stop are made of a higher durometer. The old and new Jounce Stop are
visually similar, however the NEW Stop Blocks are marked with a white dot on the end.