What causes hydraulic pump noise (ticking)? - Rolls-Royce and Bentley Forums
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post #1 of 51 (permalink) Old 11-23-2011, 03:05 PM Thread Starter
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What causes hydraulic pump noise (ticking)?

Hello Friends,

I find myself pondering what actually causes the 'ticking' noise from the hydraulic pumps. My first thought is 'lash', as with valves. That would imply wear, possibly, of the camshaft lobe or the pump's pushrod. It seems that the only repair for this is a new pump push rod (or cam). Ouch!

I then began thinking what else might cause this problem. Many of you have reported that your pumps 'tick' until warmed up. Mine get quieter when warm but the sound is still there and audible from the interior with no accessories switched on.

My car has air in the rear hydraulics and therefore needs to be bled. That got me thinking that since air is very compressible, it is the hydraulic equivalent of 'lash'. Could this be the cause of my pump's noise?

What else might cause the problem? Incorrect hydraulic/brake fluid? Gremlins?

I would certainly like to make this engine sound quieter.

-rick / '69 R-R Silver Shadow
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post #2 of 51 (permalink) Old 11-23-2011, 04:25 PM
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If you have weak accumulators this often results in pump ticking.

Have you performed the "pump test" to check the condition of your accumulators? I documented this quite a while back in the Silver Shadow Brake Issues: Your Help Would Be Appreciated!! thread.

The pumps generally expect to have some "push back" from accumulator pressure when they're trying to build it up further. If there's very little ability to build it up and keep it there ticking is one common result.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


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post #3 of 51 (permalink) Old 11-23-2011, 05:42 PM Thread Starter
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Quote:
Originally Posted by guyslp
Have you performed the "pump test" to check the condition of your accumulators?
Fantastic set of instructions. Thank you. My quest now is to find an appropriate range pressure gauge with the right fittings...

-rick
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post #4 of 51 (permalink) Old 11-23-2011, 06:03 PM
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Rick,

PM me with an e-mail address and I'll send you a set of "make your own hydraulic pressure testing gauge" instructions.

Brian

The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth.
~ Niels Bohr


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post #5 of 51 (permalink) Old 11-24-2011, 10:21 AM Thread Starter
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Quote:
Originally Posted by guyslp
Rick,

PM me with an e-mail address and I'll send you a set...
Got the instructions. Thanks!

-rick
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post #6 of 51 (permalink) Old 12-09-2011, 10:26 PM
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The ticking noise of the pump is showing it is working and quite possibly working too hard if the accumulator has a problem but to say the noisey pump is "because of the accumulator" is incorrect. The pumps shoudl be relatively quiet from inside the car, althogh it is very typical for some to be boisier than others. The pump can be removed and rebuit if teh noise nothers you. It is not expensive. I would doubt very much the cam needs replacing.

Regards,

Rodd Sala
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post #7 of 51 (permalink) Old 12-12-2011, 11:52 AM Thread Starter
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Thanks Rodd. When I get back to restoring the final bits of this car, I will examine the options. What is your cost for a pump rebuild?

-rick

Quote:
Originally Posted by Rodd Sala
The ticking noise of the pump is showing it is working and quite possibly working too hard if the accumulator has a problem but to say the noisey pump is "because of the accumulator" is incorrect. The pumps shoudl be relatively quiet from inside the car, althogh it is very typical for some to be boisier than others. The pump can be removed and rebuit if teh noise nothers you. It is not expensive. I would doubt very much the cam needs replacing.

Regards,

Rodd Sala
www-park-ward.com
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post #8 of 51 (permalink) Old 12-13-2011, 09:32 AM
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Ticking pump

Can mr. Rodd tell us wether the ticking pump can harm the engine in the long term? The sound doesn't make me very happy so to say, although in my car the ticking disappears after some time as the engine warms up.


Could it be a little more perhaps......no, it MUST be more!
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post #9 of 51 (permalink) Old 12-14-2011, 02:26 PM Thread Starter
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Hello Friends,

We have talked about the effects but, talked little about the causes of the noise. Some have suggested the accumulators. Mine are new/rebuilt but the system still ticks.

My rear pump,

1. Ticks when cold,
2. Ticks more when at speed,
3. Ticks less when hot at idle AT FIRST then, ticks more after a few seconds of idling.

The rear hydraulics need to be bled. Can air in the system augment the ticking?

-rick
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post #10 of 51 (permalink) Old 12-14-2011, 05:09 PM
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Hello,
Quote:
Originally Posted by rolindsay
Can air in the system augment the ticking?
Yes of course but only at the starting, this system of pump purges itself automatically after a while.

However if there is some nitrogen in the oil the pump cannot purge well, it's the same problem with citroen cars.

When sphères membranes are porous they let go nitrogen in LHM. It's easier to verify if you bleed rear sphères you evacuate many LHM foam.

You shoud change yours rear sphères if they are tired and your LHM.

If you have nitrogen in the LHM, you have to change all the LHM in the suspension circuit , of memory the front pump, then bleed all circuit bigining rear to front of the car, as explain in the workshop, many bleed valves

Bernard

Would you, please, excuse my bad English, I'm just french. Nobody's perfect ....
Bentley turbo R LWB 1997 & Rolls-Royce Silver Spirit 1987
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