Clutch question for the Gurus

[Trent]

So far nobody has had even a comment about this so I challenge you all!



Tell me why my truck has a "pressure relief valve" attached to the clutch slave cylinder that pops loudly almost every time I step on the clutch pedal. Dealer said this relieving of pressure is normal. This part is not in Dodge's part database as I guess they just include it with the cylinder but it doesn't show on their pictures. The pop is confirmed to be coming from this valve when you have your hand on it and someone presses the clutch pedal.



I want to understand why this valve is neccessary since so many appear not to have it on their trucks.



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[rbattelle]

Mine doesn't pop... never has! I don't think it's normal. I'd press for a new hydraulic clutch assembly (master and slave are sold together). Hopefully it's not poping because the something in the diaphragm spring on the pressure plate is messed up.



-Ryan

 

[Trent]

I'd like to think that it isn't supposed to pop either but I would need a little more than that to get the dealer to spend anymore time on it. The dealer says that this valve is there to relieve pressure. Why would it need to be there at all? Under what normal conditions would it need to actuate?

 

[nickleinonen]

Under what normal conditions would it need to actuate?

not normal, but if the linkage going from the slave was to bind/seize, you could overpressurize the system by forcing the pedal down. perhaps it is there to avoid that???

 

[rbattelle]

not normal, but if the linkage going from the slave was to bind/seize, you could overpressurize the system by forcing the pedal down. perhaps it is there to avoid that???

That's my guess. Which is why the slave cylinder needs to be diagnosed to see whether it's actually overpressurizing (perhaps from some bind in the clutch diaphragm itself), or if the valve is just shot and needs to be replaced.



Of course, that diagnosis won't happen at the dealer since they've decided "oh, it's normal".



-Ryan

 

[RedSmoke]

That's my guess. Which is why the slave cylinder needs to be diagnosed to see whether it's actually overpressurizing (perhaps from some bind in the clutch diaphragm itself), or if the valve is just shot and needs to be replaced.



Of course, that diagnosis won't happen at the dealer since they've decided "oh, it's normal".



-Ryan

This isn't actually a pressure relief valve - it's an inline damper system for the clutch hydraulics. It's there to combat pedal vibration when engaging/disengaging the clutch pedal. If you truely have a popping noise, it sounds like there's either a release system problem, or a throwout bearing/quill binding. I have heard the clutch pedal switch snap from time to time on some of these trucks, but that noise is in the cab.

 

[Trent]

RedSmoke,



You can ignore my PM, as I didn't see this response before I sent it. I have my dealer service paperwork which says "clutch pressure relief valve" functioning as normal. Is this part built into the slave cylinder, as in only one part number for the whole assembly? Geez... stupid dealers are the bain of my existence.

 

[jelag]

I would like to add..... that since this is a hydralic system and we can generate a very large amount of pressure with pedal pressure..... it might be there to prevent damage to other parts if, say someone put both feet on the pedal and pushed for all their worth... . I can see the fork bend, or as we've had on our F550, damage to the slave due to over pressure. . it will blow the end out of the slave cylinder..... this is assuming that there is something preventing the cover from functioning etc. etc...