[jeyjey]

I could use some assistance diagnosing an odd chirping sound coming from the N/S rear of SBH37222. It sounds a lot like a warped disc hitting the brake pad once per revolution, except:

It doesn't happen below about 10mph,
it doesn't happen with no throttle,
and it doesn't happen with heavy throttle, only light throttle once you're up and moving.

The period also doesn't seem to vary linearly with speed. It does change a bit as you speed up or down, but sometimes it gets faster and sometimes slower.

Is there anything in the height control valve or ram that can squeak or chirp? That might explain the non-linear frequency response.

Or do the hubs or ball & trunion joints ever chirp or squeak? (I'd think they'd be more likely to rumble if going south, but I don't have a huge wealth of experience here.)

Or maybe it is the brakes and the problem is just dependant on the rear suspension being in some narrow range of compression/movement which happens to be produced by light throttle?

(One other clue: applying the parking brake enough to get just a little bit of drag doesn't seem to change anything.)

Thoughts appreciated...
-- Jeff.

 

[jeyjey]

I'm not sure if this fits with all the clues, but I just came across a thread on the Australian forum where Paul Yorke was suggesting that sticky brakes are often the first sign of hose failure, and that the N/S/R is usually the first to go.

The last record of a hose change on my car is 14 years ago. They appear to have been done at least once after that, but since I don't know when, they're up for replacement anyway.

So I think I'll put the squeak issue on the long finger until the hoses get done and see what happens.

-- Jeff.

 

[guyslp]

Jeff,

I can't help with theories regarding the squeaking. I would definitely check out the level of lubrication in the trunnion joints, as these are often woefully neglected and allowed to run virtually dry. They tend to leak into the differential and you have no idea they've emptied out. Often the differential is found to be rather overfull when you remove the filler plug.

If you're going to replace your hoses you may wish to consider stainless braided teflon hoses if they're available and street legal on the other side of the pond. These, unlike the conventional rubber hoses, have a virtually unlimited lifespan provided they are not kinked or otherwise damaged by some flying object.

I created a full chart for SY series car hydraulic hoses in the Rolls-Royce & Bentley Parts, Repair, Restoration & Other Resources Compilation I maintain. The actual lengths for said hoses are noted at the bottom under the chart where I note where I bought mine and the cost at the time.

 

[Hemmo]

Odd chirping

Could it be a little birds-nest ..... :?:





:arrow:

 

[jeyjey]

Nah, they've all gone south for the winter.

-- Jeff.

 

[jeyjey]

Not sure exactly what did it, but my rear-end chirp is gone. Most likely candidates are greasing the drive shaft u-joints and draining/refilling the oil in the trunnions.

There was also the whole saga of the broken prop shaft nipple (see separate thread) which necessitated removing the chassis crossmember and handbrake pivot. So it's possible that was a factor, but I think it unlikely.

-- Jeff.