I suspect the wheel bearings in the car are bad. There's a loud sound that I do not think is correlated to engine speed.

What is a good way to check the bearings? Is visually inspecting them the only way?

OR I thought of this.... if i rolled down a hill with the engine off and the car in neutral, would i not hear the bearings grind?

is this an easy job. if i can change the brake pads and disc, would i be able to do the wheel bearing job? i looked online and saw an inner and outer one for the front. it does not seem that tough but i could be wrong.

your input is appreciated guys.

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Jennifer
90 350sdl

Getting the races out is a PITA. Make sure you have a firm surface and a decent sized sledge hammer. Use a 32mm or so socket with 1/2" drive extension inserted through the socket in reverse for one side and a decent chisel (or three in my case) on the other. Neutral down a hill is a starter, where is the sound coming from where does it occur?

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Maybe if you jack up the front corners and spin the wheel and see if it makes any noises under a low rpm.. then you might know something

if you do the bearings make sure you have some decent punches to get it out... the harbour freight ones like to break. and keep everything clean

I didn't have any trouble with the wheel bearings (I hope, I've only driven on the new ones for about 1 month). You need 19 mm to get the caliper off, which for me was the hard part since I had a frozen piston and the rotor was worn - couldn't get pad out. You need a 5 mm allen wrench (somewhere on one of the guides it says 5.5 mm - I spent 4 hours looking for one of those - and it turned out to be a 5 mm anyway.)

You need a punch or two and a reasonable hammer. I rented the race driver kit from AZone and those did great for putting them back in.

Here's the killer though - the bearing seal on my 1985 300 SD is listed as one thing in all the aftermarket systems (AZone, ADV, Oreilly, PepBoys, NAPA) and it doesn't fit. Ruined two of those before I got smart and held it up to the old one. Clearly different in diameter and depth too. So I got them from the MB dealer and it went it as it should, with a little force.

Would have been a 2-3 hour job if I had known three things - the allen wrench size on my car was different from the one in the guide (http://207.210.95.34/~boostd/Maintenance/Bearing/) and hadn't searched everywhere for it. Also, had I gotten the seal from MB (they had to order 1 in) instead of aftermarket stores (they do have the right bearings, size 3 and 5 I think). And finally, that my caliper was bad and I would have removed it immediately instead of trying to pry it open.

Also, I looked all over for Red Line CV-2 grease just to feel good about it (I think it's overkill for this application), but I couldn't find it locally and it was pricey to order it online. I think I used the SynPower kind.

This all started as a brake job for me by the way.


Good luck.

MY brake job was a combo that started as a wheel bearing job. The left fron wheel bearings had no wobble to them, but when I spun the wheel by hand, I could feel it "clocking", when spun it sounded like a very dull ratchet, but it would start roaring at 30 mph, and get louder as speed progressed. No need to shut the engine off, but coasting in neutral confirmed a wheel bearing.

I found a caliper with a slight leak and both had torn piston dust shields, so a brake job was incoprorated as well.

To be safe, I replaced all the bearings/races on both sides, as well as the calipers, pads, rotors, sensor leads and rubber lines.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

91 W124 300D Turbo replaced, Pressure W/G actuator installed. 210K

90 Dodge D250 5.9 Cummins/5 speed. 400K

See if the noise changes when you turn the wheels. If it changes as you load/unload the bearings that would tend to indicate that they are bad.

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80 300SD (129k mi) 82 240D stick (193k mi)77 240D auto - stick to be (153k mi) 85 380SL (145k mi) 89 BMW 535i 82 Diesel Rabbit Pickup (374k mi) 91 Jetta IDI Diesel (155k mi) 81 VW Rabbit Convertible Diesel 70 Triumph Spitfire Mk III (63kmi)66 Triumph TR4a IRS (90k mi)67 Ford F-100 (??)

Best description of diagnosis.

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83 SD

84 CD

Mine was only noticeable at <5mph.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42