Rattling P/S pump

[a67]

What causes a P/S pump to rattle? It rattles a lot when cold. Gets a little better as it heats up. This is on a 1st gen Firebird. Stock GM pump.



The noise is driving me crazy.

It was fine until I replaced the seals. All I did was pull the pump apart, cleaned and painted it (outside only). Put new seals, o-rings and such in, and bolted it back up. Yes, the vanes were out, and put back in the same direction.

And the rattling started. I even pulled the pump apart again and found nothing amiss. Any ideas?

a67

[MrQuick]

is your pulley nut torqued properly?

[a67]

It should be, but I'll check it later today. Only take a minute to be sure.

a67

[67 goat]

My '67 GTO does the exact same thing! I'm not sure exactly when it started, but I've noticed it within the last couple years. I can only hear it at idle and only if I lift the hood or put my head near the grille. I haven't noticed any performance issues, so I've just left it alone for now.

My permanent solution was to install Flowmaster's Super 44s. I can't hear any noise coming from the P/S pump now!

[a67]

67_goat, interesting that your P/S pump started doing it over time. What I now think has happened is that the vanes wore into each slot of the rotor. And by mixing up which vane was originally in which slot, they now hang up a little and rattle.

In your case it may be that the pump vanes and rotor are worn. But there is some good news. The pumps used up through at least '85 (and probably newer) use the same guts. Even the cast iron body is the same casting number.

To back up a little, I checked the pulley nut, not as tight as spec. Torqued to 60 ft/lb. Checked crank pulley bolts, not as tight as spec, tightened those up. Replaced some fluid with a partial flush & re-fill with GM P/S fluid.

Still rattles. No difference, a clacking type of rattle. FSM states three causes: loose pulley nut, high pressure hose hitting, vanes sticking or improperly installed.

I'm with the sticking vanes theory now. So, I grab some other pumps I have around, one being from an '85. And another '67 pump body (that also rattles and has been apart for new seals).

Took the guts out of the '85 and put them in the '67 body. AND, made sure that the vanes were not moved. They are in the exact locations and in the exact position as they have been since being built.

This pump will be bolted on either later tonight or tomorrow. If it rattles, maybe I'll go with manual steering

a67

[a67]

Well, not only does it still rattle, but I don't have any pressure. No assist, blah. Don't know if I assembled the pump incorrectly or if there is a compatibility issue between the years. But that doesn't matter as it stills rattles.

I need to figure out this clacking rattling sound. It sounds horrible. I guess it can't be a sticking vane issue. But what is it? Pressure regulator valve? There has been two different valves in the box and the rattling never changed.

Remove the belt from the P/S pump and the engine sounds great. The belt ONLY drives the pump, nothing else.

Put the belt on and the noise is back. No belt, no noise. I'm even beginning to wonder if the belt may have a problem. Or maybe a hair of run-out in a pulley is causing the pump speed to vary. Or something...

I even put a block of wood up against the pulley nut/shaft and put backwards pressure on. Just to see if the noise was from the shaft running forward and aft. No difference.

Typing this out is helpful. Maybe the noise isn't really the pump, but something that is affecting the pump. Maybe the box has a problem. There is also a cooler on the return line. Maybe something up with it. I do know that I am going to figure this out. And of course fix the pump so there is pressure, lol.

No belt, no noise. Belt on, severe noise but the steering is fine (with the previous pump). What am I missing?

a67

[David Pozzi]

Check out your crank pulley, mine cracked and made noise. The PS pulley has a lot of offset which puts a lot of stress on it near the bolts.

Use a piece of fuel line as a stethiscope to detect where the noise is coming from exactly. don't forget to check the pump brackets.

I've had new pumps fail to start pumping, after letting them run a good long time and giving the engine a few revs, the pump came to life again.

[a67]

Success. It is quiet and have pump pressure back. Short side: the crank pulleys were moving, and I put the original pump back in.

Long side: used a piece of heater hose and the clacking was a little louder once I moved to the inner area of the crank pulleys. Hmm, OK with some luck the crank pulley is cracked. That way I'll know that this is the issue.

Nope, pull crank pulleys and no cracks. OK, now what. The three mounting bolt holes are elongated. This is a triple groove pulley set up. Inner pulley with two grooves, then an outer with one groove (for the P/S pump).

Can see that there was motion as the metal under the mounting bolt heads (with split locks) was worn away. Along with the egg shaped holes.

So i scraped the paint off the pulleys where they met (I like to paint everything, so this is paint I applied years ago). Cleaned up the metal around the bolt holes, the split locks like to dig.

Then used three GM bolts with integral washers (shouldered heads) for pulley mounting. Also used a GM bolt and washer to retain the damper. It was originally an aftermarket bolt/washer.

Bolted the pulleys back to the damper along with the damper bolt with some blue Locktite. Put the belts back on, and couldn't bring myself to start the engine.

The Locktite needs to set up, right, lol. Anyway, finally hit the key, and, and, no noise. Son-of-a-gun. So that fixed that.

But, still no power assist. Ran the engine for about 20 minutes, rev'd it up, held it, let it idle, rev'd it up. Dang, still no assist.

OK, time to pull the pump back off. Do that, open it up, check the pump cam. Figured that just maybe I put it in backwards. Nope, it's in the right way.

I'll deal with that later. Grab the original pump body assembly, install that into the reservoir and reinstall onto engine. Bam, have pump pressure. Bleed, fill, short drive, check level, life is good.

Now, I feel as though the pulley noise will return. A quick rev'ing engine with the alt, A/C, and P/S loads will loosen it up again. When it does the game plan will be to strengthen the mounting. Increase the pulley mounting bolts to 7/16" or 1/2". True up the two piece pulley alignment and weld them together (the pulleys, not to the damper).

Maybe even find some time to pin the pulleys to the damper. We'll see what happens.

a67

[David Pozzi]

Are you using a stock 67 low performance pulley set?
I think you can buy reproduction crank pulleys.

I welded mine together and welded thick washers over the holes. I'm not so fond of spit type lock washers. They concentrate force and dig in causing all kinds of trouble. I'd rather see a star washer or plain washer and locktite used.
David

[a67]

Yes, the standard run-of-the-mill pulleys. If at all possible I'd like to stick with the GM pieces.

I like the idea of welding washers over the holes. Can do that when the pulleys get welded together. I also checked out some SBC flywheel bolts I have.

Large diameter heads, grade 8, 7/16" fine thread, with star washers (stock GM stuff). Used in good condition. Look to be a decent candidate for upgrading the clamping.

Unless the noise returns in the near future I am going to wait until Winter hits. I enjoy driving the car too much to take it apart at the moment. Had her out yesterday for about 40 minutes. Was really nice not having to listen to the clacking rattling noise.

a67

[a67]

To finally close this thread out, I had some time to look over the pump that didn't pump. This one had the guts from an '85 in it.

I also had a '67 pump on hand to compare it too.

There is only slight differences between the two pumps. The pump casting on the '85 had two holes side-by-side drilled through to feed oil to the outlet port. Where the '67 had a single slightly larger hole for the same feed.

Other then that the pump casting was the same. Same casting number and nearly the same machining.

Pump: the only difference is that the '85 pump has thinner vanes, and a very slight difference in the pump cam shape. The difference in pump cam shape can't be seen unless the two pump cams are placed on top of one another (it may also be that the '67 cam has more wear).

The '85 vanes, however, being thinner are lighter. By design the pump feeds high pressure oil to the rear of the vanes. This is done to press them out onto the pump cam. So upon initial rotation the vanes need centrifugal force to start the pumping of oil.

Then once pressure starts to build the vanes are forced out by the oil being fed in behind them. Interesting design. And, is along the lines of what David mentioned about sometimes needing to give a pump some time before it will provide pressure.

Given more time and RPM this pump would most likely had worked. At the time I wasn't sure that there wasn't something else wrong with it. So went back to the one I knew provided pressure.

One item that was added to the '85 pump was a magnet. A small disk magnet was stuck to the casting on the lower portion. About an inch in diameter and 3/16" thick. It ended up in the pump that is on the car now.

a67

[a67]

I don't really won't to bring this thread back to top. That means the original fix didn't work. Lasted about two 20-minute drives.

However, since it has been so long since the latest "fixes." I think I've got it now.

After the above mentioned changes the rattling returned. The interesting part was that it was a light clicking sound. Just like it was 10 years ago.

Click-click-click-click-click-click-click-click-click-click. Rapid and light. Just like a P/S pump would be expected to make.

So: removed the pulleys, removed the damper.

Drilled and tapped the damper pulley bolts to 7/16"-20

Drilled out the pulley mounting bolt holes to 1/2"

Used 3/8" grade 8 washers (3). Bored the openings to _just_ fit a 7/16" bolt. The bolts used are grade 8 SBC flywheel bolts.

Put Damper in lathe mounted by the hub snout. Mounted the 2-groove pulley and then the 1-groove pulley on the damper. Just snug.

Using a dial indicator tapped, prodded, and convinced the pulleys to a minimal run out location.

Worst was something like 24-thou. Was able to get them within 5-thou. Used the dial indicator on both the top pulley surface and lower groove surface. Just trying to get the least run out.

Then tightened the pulley mounting bolts to the damper.

Ah, forgot to mention. The bolts had a short aluminum sleeve on them. Between the head and the washers. This was to keep the welding heat and flame off the bolt heads.

Removed the damper/pulley assembly from lathe. Tig welded the grade 8 washers with the minimal clearance to the pulley. Welded the pulleys to each other.

The welding was minimal. Enough that I felt it would hold. But not so much that heat distortion or an unbalance would result.

Pressed the damper back on and installed the pulleys and belts. It has now been a while and no noise. Much better, and I'm hoping the noise stays away.

Because if it doesn't, then I'm just going to make or obtain a 3-groove billet or cast set up. One way or another I'm not going to put up with the clicking or clacking noise.

Bob