Caddy Posted January 8, 2013 Share Posted January 8, 2013 Hi, Does the Chieftain's main brakes need the engine running to work? On Sunday I was asked to remove the master cylinder out of our Chieftain and strip and clean it. Apparently the thing was siezed. So I stripped the moving parts down, cleaned them up, and re-assembled them. All moving smoothly. I haven't touched the hydraulic side of the master cylinder yet. When I re-installed the cylinder I tried the pedal and it was still solid. The pedal itself is quite stiff, but I can't see this being a problem. Any thoughts? Quote Link to comment Share on other sites More sharing options...
VMA Tiffy Posted January 21, 2013 Share Posted January 21, 2013 Hi, Does the Chieftain's main brakes need the engine running to work? On Sunday I was asked to remove the master cylinder out of our Chieftain and strip and clean it. Apparently the thing was siezed. So I stripped the moving parts down, cleaned them up, and re-assembled them. All moving smoothly. I haven't touched the hydraulic side of the master cylinder yet. When I re-installed the cylinder I tried the pedal and it was still solid. The pedal itself is quite stiff, but I can't see this being a problem. Any thoughts? Hi Caddy Haven't done it for a long time and if my memory serves me right, the master cylinder will be solid until you start the engine and then it will depress slightly as the pressure is dissipated around the system. The 'M' type pump will probably need bleeding and the accumulator fully charged with air (30 bar? or was it 30psi?). The accumulator will provide an emergency operation of the brakes in case of engine failure. The whole system will need bleeding and this is done with the engine running. Hope this is helpful. Quote Link to comment Share on other sites More sharing options...
Markheliops Posted January 21, 2013 Share Posted January 21, 2013 Hi Caddy When you say the master cylinder are you referring to the brakes or steering. As a thought - surely you will have to bleed the system if you have had the master cylinder out? However, if the pedal is solid - I can't see the fault being air in the master cylinder. If air is in the system the pedal would surely go down to the floor. Going from memory because I haven't had any issues with my ARRV brakes, I would suggest if the brake pedal is solid then the fault will lie in the main brake valve unit possibly being seized or the master cylinder as you suggest. The brake pedal should still move without the engine started. I may be wrong and others feel free to disagree as I haven't looked at my brakes for quite a while. Markheliops Quote Link to comment Share on other sites More sharing options...
Caddy Posted January 21, 2013 Author Share Posted January 21, 2013 Thank you both, It's the main brakes, not the steering system. The brake pedal didn't want to move and she didn't want to stop. Removed the pedal and cylinder (more of a gate valve than a cylinder). Cleaned both up and re-fitted. thought we might need to get the main engine running to bleed the hydraulics. But really good to know we are on the right track. We've got the steering system to bleed as well. After working on the IWM's Cent mkIII it was quite surprising to find a tank with a hydraulic system again...... Quote Link to comment Share on other sites More sharing options...
examech Posted January 27, 2013 Share Posted January 27, 2013 Main brakes are a fully pumped system. The pedal valve is, as you say, a gate valve. Accumulator air pressure is 600psi, engine stopped and pedal pumped until residual pressure has been dissapated. I have the user handbook and can send you extracts if that would be any use. Quote Link to comment Share on other sites More sharing options...
Caddy Posted January 28, 2013 Author Share Posted January 28, 2013 Cheers, that'd be brilliant! I'll PM you my email address. Quote Link to comment Share on other sites More sharing options...
tankie88 Posted February 11, 2013 Share Posted February 11, 2013 A Chieftain with a main brake that will be a novelty. Quote Link to comment Share on other sites More sharing options...
Caddy Posted February 12, 2013 Author Share Posted February 12, 2013 A Chieftain with a main brake that will be a novelty. Granted, but as we lost the anchor we had to find a way to stop it running over spectators - it's bad for repeat business. Quote Link to comment Share on other sites More sharing options...
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