den458

Question about 2003 2WD Astro possible power steering pump moan or groan sounds:

ONLY as I apply brakes and speed decreases to about 8 mph, I hear a moaning sound in the engine compartment that remains almost until the van comes to a complete stop. The moan will continue as long as the van remains moving about 3-5 mph and brakes remain gently applied. Moan stops as van completely stops. The brake rotors and pads appear fine. Problem definitely NOT a grinding, metal on metal sound. Is it the power steering pump? Is replacement the only solution?

Background: Bought 5 years ago with 70K miles, van now has 142K miles, has been reliable, would like to extend useful life. Moaning sound is a nuisance I'd like to resolve. Moaning sound is NOT new, I've noticed it for quite a while, I've just tolerated to moan to this point, should have investigated it sooner, but van has always stopped fine. Would much appreciate any insight into problem prior to taking van for diagnosis at GM dealer. Sorry if this should be posted in another category, thanks in advance.

stevejohnson48

Your van power steering pump operates both the brakes and the steering , I had the replace mine because nether the brakes nor the steering worked , got close to having it out , reached up on the pully,and the thing started to come out of the unit ( shaft sheered)scary, I rede somewhere its moan is normal under the condition that the hydro boost system on the brake side cause's that. I don't know what mine sounded like before it went out, so I can't help you there,but after installing the new one it still moans,go to power steering pumps,and replacement in this site , and a better site for astro's is AstroSafariVans.com , don't know if I'm suppose to recommend another site but there it is,Steve

johntaps

Sound like bad steering pump.

den458

John, do I understand you correctly, that after pump replacement, yours still makes a moaning sound like I describe? Thanks, Den

den458

Sorry, I meant this question reply to Steve.

stevejohnson48

Yah, mine still moans and grunts,above normal,compared to any other vehicle that I've owned ,but like I said , somewhere in a article that I read they indicated that that was normal under the circumstances ??? after I found out it was out ,I went and talked with a friend that's a 4x4 nut along with reading about 4x4 steering box's in a earlier project, and finding out that they make BEEF up box's for big tires and rock crawling,I was thinking that WOULD BE THE WAY TO GO ?? then taking to Dough about it , he indicated that a more powerful box,might make it over or under correct ,at different speeds,(not being road friendly) so I decided to go with the stock box, let me know if you find out any thing different ?? Steve

RacerX

Are you sure you dont have air in the pump or a low fluid level? Even a bad belt?

den458

Thanks for replies. All steering & brake fluids are fine.

I just pulled the 60A ABS fuse under the hood, took it for a test-drive, & the moan disappeared, brakes sound perfectly normal & quiet while braking, beginning thru full stop. The ABS dash lamp is now lit with fuse pulled. The moaning sound while braking my 2003 2wd Astro is ABS related.

I recently rode in a friends' GM pickup truck of about the same age, his brakes made a similar moan. I told him mine has a similar moan. He said the dealership said his truck had a dirty ABS sensor, replaceable &/or potentially cleanable. He declined both options as expensive... he just ignores the brake moan.

I re-installed the ABS fuse (I know I could leave it out). Now that I know its ABS related, any ideas from the forum on how I might isolate it to a sensor & process to clean it?

RacerX

sensors dont cause noises like that they just read the signal. PLus there are no ABS sensors in the engine compartment. The ABS hydraulic control module is bad. Very expensive maybe Autozone has reman'd units.

den458

Since its ABS related for sure, I now think I might have been wrong about where I thought the sound was coming from. I thought it was engine compartment, but it is really ABS pulsing the brakes. Rapid brake pulsing by the ABS creates the sound I thought was a moaning sound.

I understand the sensor is not the source of the noise, but could it be the cause? Is it possible that the sensor could be giving bad input to the ABS hydraulic control unit, causing the ABS to activate when it shouldn't?

I'd rather chase something simpler & less expensive like a sensor, if it might be the root problem. How can I be confident it is the HCU, & not the sensor?

I appreciate your continued patience & input, while I soak up this education, thanks.