[Roger]

Are you confident 20 plus year old hoses are OK? You are working in that area now, will it be more convenient to change them later?

[Marius]

Air brake hoses are pretty cheep at your local truck fleet supply.

[Archived]

Checked for air hoses and some of mine still have part #s on them Parker brake hoses, Truck parts wanted to go to 3/8 and bush 1/2 inch NPT down to 3/8 and no springs on ends, did not want to go there so I talked to William Plumber at Prevost and we looked at air schematic and break down and I measured each line 8 total and we came up with the correct part numbers 5 different sizes and they are all Parker with springs, it will take a couple of weeks to get them all but were not going away for awhile. Here is a picture of Prevost parts shelf.

[Archived]

They (including Bendix) say not to change the diameter and length of hoses. It’s engineered and has to be balanced. Each brake needs to apply at the same time. Be careful when replacing valves such as the R14 relay valve. They have a tag stating the crack pressure. If you buy a valve at the local parts store make sure the crack pressure is the same.

[Art]

EVERYTHING in our brake system is carefully engineered and sized so the braking forces are balanced.

The size of brake chambers, the size and length of hoses, the area of the brake friction material and disk or drum and even the length of the slack adjuster arms all contribute to the balancing of forces.

It is very important as has been mentioned above to duplicate the original components because of all the factors involved. Our brakes generally speaking are lousy and we need to make sure we do not make them worse. Prevost has pointed out in seminars, as well as Bendix about how much engineering goes into system design to meet the stringent standards for performance.

[Harry]

All the Relays came from Prevost one R-14 and three R-12 all bendix and all the same that came off.