[Archived]

I put new brake chambers on the drive and tag. The oem tag is a 16 service 24 parking (16/24). The numbers correlate to the diameter and volume. I put 30/30 on the tag because the supplier said it would fit, and it did even though the bolt pattern on the 16/24 is 3 inches and the 30/30 is 4.5 inches. The oem mounting bracket is designed to accomodate either size. Questions I had in doing this were 1) will the diameter of the 30/30 rub against the air bag? Answer: No, 2) will the tag wheels/tires lockup and skid? Answer : No, 3) will the tag trigger the ABS? Answer: No.

So all my previous brake problems are history. The parking brake releases correctly, the parking brake holds when set, and the service brakes perform much better.

Caveat: be vintage sensitive to all my comments.

[Mike]

Dan,

You should have installed 30/36. They are sized that way for a reason. The first is the spring brake is an emergency brake and there is no way a 30 will provide the emergency stopping force of a 36. But as a parking brake you also need a 36 because the 24 on the tag is pretty anemic and is only going to supplement the drive axle parking brake.

But if you disagree you are more than welcome to back 3/4 of the way up my driveway, and then step out of your coach. If it remains in place I will gladly eat a full serving of crow.

The reason we have such weird sizes on our coaches is to balance the braking forces our axle weight limits need. If we go too big we have premature lock up, and if we go too small we might not be getting all the braking force our drums or discs can provide.

[Greg]

To be clear, I did install 30/36 on the drive and 30/30 on the tag. Seems to be working well so far.

[Archived]

Understand now. It will lock up prematurely on wet or slippery conditions.