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New Day...New sound...This one sounds awful

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79Spit

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Bought a '79 Spitfire a couple weeks ago. Been having a great time trying to find all the little crazy things that come with the car. This one is significant though. There is a real grating sound coming from the rear driver's side tire assembly. Definitely metal on metal, and occurs mostly at lower gears, at initial acceleration. When the truck transport guy brought my car me from Michigan, he said he thought the rear differential fluid seemed to be leaking a little. I have been looking under the car, but did not see any drips or puddles. I made an appointment with a mechanic who does Triumphs and MGB's exclusively for Monday morning, but I would like to at least try to troubleshoot this before I bring it to him. How do I check the differential fluid level on my Spit, and would there be grinding sounds in the rear wheel assembly if the fluid level was quite low?

Thanks in advance for any and all insight...
 
Could be something as simple as a dry U-joint, I don't think low diff fluid would give you that symptom.

but there is a plug on the drivers side, usually with a square on it that you undscrew, the fluid level should be at the bottom of the hole.
 
Have you tried something as simple as jacking the rear of the car and turning the wheel by hand? My gut feeling is that you've got a bad wheel bearing. If it's making that kind of noise, you're probably looking at new bearings...AND a new axle shaft (which serves as the bearing race and probably is chewed up now).
 
Would wheel bearing noises go silent when coasting? The noise is "usually" only occurring when I accelerate. When I hit 40 or so, it goes away.
 
possible, but I don't think likely.

This is going to be something like a brake shoe retainer that has come loose and allowing the shoe to rub against the drum or something along that line.

get the tail in the air and give everything a good shakedown. Something's twisting under load. Something like a perished suspension bush would do it.
 
Had mechanic jack it up just now and take a look at things. All assemblies looked OK. Took the brake hub apart. that was fine. Nothing is visibly rubbing anywhere. He was of the opinion that bad wheel bearings would lead to a constant sound. This one almost always goes away when I coast. The wheel was secure and the frame was not grinding on anything. The mechanic was ran out of ideas. He thought everything looked fine, though he is not a Triumph specialist. I have an appt with a Triumph guy Monday, so at least today I think we determined that the wheel won't fall off while I drive on Monday. Just going to be a noisy, embarrassing ride. The noise is definitely "rotational", i.e. that is, what sound like "grinding pulses" increase in frequency and noise level as I go faster. When I am up to 40 MPH or so, they die down, and if I am not accelerating, they die down as well. Anybody have any other ideas?
 
Mechanic did say he thought there should be a few more bushings in the rear end, but the other side of the car didn't have any either, and it is not making any noise. There were bushings under the leaves of the leaf spring, but none where the upper end of the shock met the frame (and there is a big gap there - like 1/4") He cut up some rubber pieces and jammed them in the gap, but the noise still persisted, undiminished.
 
If the input shaft bearing to the differential has spun.....

High loads = spinning / grinding noise. No load might be none or small noise.

Not having proper bushings installed is a bad thing. Get a set and have them pressed in. If yours are as bad as you say, the difference will be dramatic.
 
My guess is the u-joints in the axles....
 
Took the Spit into the triumph mechanic (yes, he specializes in LBC's). will let you all know how bad the prognosis is in the next day or so. I soooo want that car back while we have Indian Summer here in New England. 95 degrees today! Doh!
 
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