Crown 35RRTT:
Brakes Locking Up

brakes work fine when cold, as day goes by they get hot and lock up. Brake pads have been replaced several times. Slave cyclinders were replaced 2/1/07 by crown did not resolve problem. Any Suggestion?
  • Posted 2 Feb 2007 07:13
  • Discussion started by albert_h
  • California, United States
Showing items 1 - 3 of 3 results.
If the problem is the caster brakes locking up, let me explain a few things. The caster brakes are applied by a spring that pushes the plunger into the master cylinder that apples the brakes. When you lift your foot off the pedal, the spring pushes on the pushrod which supplies pressure to the caster brakes and applies them. You should take the floorplate off the truck, push the brake pedal down all the way, and make sure the pushrod that applies the caster brakes is completly retracted when you push the pedal down. I basically just shake the pushrod to see if it is loose. If if is loose, this means the rod is not in contact with the plunger in the master cylinder and not supplying fluid to the caster brakes to apply them. You may need to adjust the linkage to get this right.
If this linkage is not adjusted right, you will get the problem you are having.

The pushrod goes into a master cylinder through a washer that is held into the master cylinder by a snap ring. If you adjust the linkage to retract the pushrod too much, you will yank this washer and snap ring out of the master cylinder when you push down the brake pedal.

The master cylinders have a tendancy to have the plungers stick. When you step on the brake pedal, the piston in the master cylinder may have not come all the way out causing the caster brake to still be applied. This will also give a false indication of the linkage being adjusted correctly when the piston sticks. It could also be another cause of the problem you are having.

This truck has a funky brake sytem. The drive motor and caster brake are both applied by a spring when you lift the brake pedal. The drive motor brake is applied directly by a spring. The caster brake is applied hyraulically by the spring on the linkage to the caster brake master cylinder. The two master cylinders work opposite of each other. When one is building pressure, the other one is releasing it's pressure.
  • Posted 9 Mar 2007 14:26
  • Modified 9 Mar 2007 14:27 by poster
  • Reply by Liftdoctor
  • Indiana, United States
We've narrowed it down to when the brakes are applied throughout the day it builds pressure locking up the brakes. Overnight pressure does release. We've changed the entire caster assembly problem still remains.
  • Posted 9 Mar 2007 03:52
  • Reply by albert_h
  • California, United States
Read the message in the Crown section for "uneven braking." Also, don't use the brakes to stop this truck. The brakes were designed for parking and emergency stopping only. You should plug the truck to stop. If you use the brakes to stop this truck all the time, you will have to continuioslly repair the brakes.
  • Posted 3 Feb 2007 13:29
  • Modified 3 Feb 2007 13:31 by poster
  • Reply by Liftdoctor
  • Indiana, United States

Post your Reply

Forkliftaction.com accepts no responsibility for forum content and requires forum participants to adhere to the rules. Click here for more information.

Having trouble using the Discussion Forums? Contact us for help.

Movers & Shakers
Linda Häkkilä Linda Häkkilä
vice president, Investor Relations, Konecranes
vice president operations, Elokon Group
President, EP Equipment Europe
Senior vice president human resources, Kalmar
Latest job alerts …
Dubuque, IA, United States
Louisville, KY, United States
Louisville, KY, United States
SMV (Konecranes) 33-1200C
Balling, Denmark
Used - Sale
Nagano NUZ090D
Yokohama, Japan
Used - Sale
Fact of the week
On average, people read 10-30% slower from a screen than from paper.
Upcoming industry events …
May 09-11, 2025 - Bangalore, India
October 21-23, 2025 - Panama City, Panama
July 15-17, 2025 - Hong Kong, Hong Kong
Fact of the week
On average, people read 10-30% slower from a screen than from paper.