1953 power steering noise

[aussiepaul]

Hello,
just wondering if anyone can give me some advice,
when my 53 coupe  has been driving for 15-20 mins there is a noise from the power steering,it's a hissing noise like oil passing over a relief valve,
if you turn the wheel it stops but starts again when driving straight.It only happens when it warms up,I've checked the usuals,nothing out of the ordinary,just wondering if anyone has had a similar problem
Thanks

Paul Wallace 

[P W Allen CLC# 20193]

Paul,

Funny thing, my 53 does the same thing, only opposite. I get the hissing sound when turning only. No sound at all when driving straight. I've changed out the pump a few times in an effort to solve the problem, but there was no difference. I believe my problem is in the steering box itself. But it works fine. I've just been living with it. Your problem must be more annoying though, with the hissing sound while driving straight. You've already checked the usualls. The only thing I could suggest is check the hoses if you havn't already. They can collapse internally and cause flow problems. Probably not so much on the pressure side, but on the return. Hope you work it out.

[dadscad]

Does your car have a rag joint between the steering gear and steering column? If it does be sure the rag joint is in good condition and the pins are not touching the opposing plate cut outs. Any metal to metal contact will transfer noise up the column into the passenger compartment.

HTH,
David

[P W Allen CLC# 20193]

Dave,

No, 53's don't have a joint. The shaft goes from the box, right up to the steering wheel. I believe the joint came out in 54.

[Whit Otis, 1188]

I don't own a '53, but if you are hearing this hissing sound, my guess is that the pump output is dumping over the relief valve thus making the noise.  Have you felt the fluid reservoir to see if it is getting extremely hot after driving the car?  This would also indicate the pump "spilling" over the relief valve.  The early power steering systems consisted of the pump with relief valve, mechanically operated servo valve and the steering cylinder.  When you turn the steering wheel, it moves a spool in the servo which ports fluid to one side or the other of the cylinder pistion.  The cylinder is linked to the servo so when it the cylinder has moved the prescribed distance, it "catches" up to the servo valve and shuts off the oil to the cylinder.  The only thing that could cause the pump to dump over the relief would be if the spool in the servo was blocking the flow.... but, not being thoroughly familiar with the system (never having rebuilt one) I would have to do additional study  to confirm or deny this statement.  The other possibility would be failed piston packing in the cylinder, but since you indicate the noise is coming from the pump, and you don't indicate any irregularity in steering effort, it seems unlikely that the cylinder would be the problem.

Whit