• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

85 245 customer car phantom driveline/undercar noise

pat244ti

pat244ti

Moderator
Staff member
Joined
Dec 23, 2002
Location
Santa Cruz CA
I have a customer/friends dad who bought an 85 245 out of Portland from the infamous Rich….

So far he’s been satisfied with the car for the most part. I did find evidence that leaves me to believe it has 150k more miles than the odometer claims. But he’s complained of an intermittent, alarming noise it’s making.

He claims it’s coming from the rear end. When it happens, he claims it sounds like a piece of metal, plastic or a branch dragging under the car. No apparent way for it to recreate the noise but shaking the wheel back and forth makes it go away when it happens according to Jeff.

I’ve literally checked everything except inside of the diff (fluid level fine) and found nothing wrong at all. Everything in the driveshaft feels fine - ujoints/support/etc. Pinion yoke feels fine. Rear suspension and bushings feel and look fine. Rear wheel bearings don’t have play, emergency brake parts are all oriented and installed correctly. The adjustment on them was tight but I backed them off. Nothing like mudflaps are loose and dragging.

I’ve drove the car for about 2 days and it’s never made the noise. I’ve rode with him for an hour or so total and it’s never made the noise.

Anyone ever heard a weird noise like that and found an explanation I might be missing?
 
Khrrck said:
Rearmost muffler still attached to its pipes?

Brake dust shields straight and not contacting the rotors?
Click to expand...
Yes and yes.

I’ve looked at everything that could possibly touch the rear brakes and anything connected to the chassis or driveline that could shift or move around. Everything including all of the engine and transmission mounts look ok too.
 
Sticky brake caliper piston, or a bit of surface rust on the rotor after getting wet? Is the noise continuous, or is it cyclic / modulated like a tire once-around? Or the old prank of putting pebbles in the hub cap? (I'm not sure if this works with common Volvo hub caps.)
 
bobxyz said:
Sticky brake caliper piston, or a bit of surface rust on the rotor after getting wet? Is the noise continuous, or is it cyclic / modulated like a tire once-around? Or the old prank of putting pebbles in the hub cap? (I'm not sure if this works with common Volvo hub caps.)
Click to expand...
I have no clue what the noise actually sounds like - only Jeff truly knows but he claims it’s a horrible dragging and it goes away with steering input. The last time it happened according to him, it didn’t go away after steering and he had AAA tow the car back to his house because he was worried it was permanent now.

I came over this morning to where it was towed, jacked up the rear and had him run it and heard nothing so I took the car from him and have been driving and poking at it all day. No noises.

The one thing I did notice when I took the brakes apart was a weird groove (barely catches a fingernail) on the inside of the drivers side rear caliper. No evidence of a sticking caliper in terms of pad wear or driving behavior (doesn’t pull)
 
Maybe a rock caught between the rotor and backing plate? Any nooks or crannies that line up with the groove?
 
bobxyz said:
Maybe a rock caught between the rotor and backing plate? Any nooks or crannies that line up with the groove?
Click to expand...
I talked to Jeff this evening and he said his most accurate description was it sounded like a metal coat hanger was ran over and got stuck on the rear end.

The backing plate was the first place I checked. Nothing. Same with the ebrake. The ebrake seemed to grab very firmly with little effort though and just in case some minor lack of tolerance was causing it I backed the cable nuts off a few turns.
 
Last edited:
I've had a rock stuck against the rotor, don't recall what it sounded like, but it was constant until I found it and removed it.

Could be a rear wheel bearing allowing a shift til axle touches something that's not spinning? But you should/would see that. And probably experience low brake pedal if pads also got knocked back with that much slop....so that seems unlikely, too. I don't recall the back of the wheel studs being so close to the parking brake hardware that this might even be plausible.

Keep hunting...
 
towerymt said:
I've had a rock stuck against the rotor, don't recall what it sounded like, but it was constant until I found it and removed it.

Could be a rear wheel bearing allowing a shift til axle touches something that's not spinning? But you should/would see that. And probably experience low brake pedal if pads also got knocked back with that much slop....so that seems unlikely, too. I don't recall the back of the wheel studs being so close to the parking brake hardware that this might even be plausible.

Keep hunting...
Click to expand...
I actually got to one side and found some really strange looking replacement wheel studs and was hopeful maybe they had a thicker backing area and maybe that was hitting…nope

The miminal play one side has isn’t enough to create bad knockback, or in general enough play to hit anything else. I don’t see anywhere that is rubbing.

I don’t have a lot of space to work on it at the moment. I really want to hear the noise before I do anything more drastic but my next blind check when I get the opportunity is to yank the axles out and check the bearings and races, and pop the diff cover off and have a look inside.
 
pat244ti said:
I have no clue what the noise actually sounds like - only Jeff truly knows but he claims it’s a horrible dragging and it goes away with steering input. The last time it happened according to him, it didn’t go away after steering and he had AAA tow the car back to his house because he was worried it was permanent now.
Click to expand...

OK, I'll toss out a crazy idea: perhaps something actually is being dragged under the car? An object in the road that he didn't see, it gets caught, and then the steering input has the effect of a dog shaking something loose? (And then he neglected to look in the rearview mirror at the moment the noise stopped, to see what it was?) Everything you've mentioned points to this possibility, except the recurrence thereof. (But maybe he keeps running over things.)

A noise or vibration can be telegraphed through the car very effectively. Sure, location often correlates... but the mere fact that it sounds like it's in the rear doesn't provide absolute proof that it is.

Especially since you've systematically eliminated so many things, by far the best approach would be to return it to Jeff's hands with a new set of instructions: next time you hear a noise, DO NOT attempt to alleviate with a steering shake, but pull over gently at the earliest convenience, and LOOK UNDER. A very strong flashlight (even in daylight) would be a useful companion.

Intermittent issues can be so maddening. Anything the doctor can't catch in the act is hard to treat.
 
Toybox said:
OK, I'll toss out a crazy idea: perhaps something actually is being dragged under the car? An object in the road that he didn't see, it gets caught, and then the steering input has the effect of a dog shaking something loose? (And then he neglected to look in the rearview mirror at the moment the noise stopped, to see what it was?) Everything you've mentioned points to this possibility, except the recurrence thereof. (But maybe he keeps running over things.)

A noise or vibration can be telegraphed through the car very effectively. Sure, location often correlates... but the mere fact that it sounds like it's in the rear doesn't provide absolute proof that it is.

Especially since you've systematically eliminated so many things, by far the best approach would be to return it to Jeff's hands with a new set of instructions: next time you hear a noise, DO NOT attempt to alleviate with a steering shake, but pull over gently at the earliest convenience, and LOOK UNDER. A very strong flashlight (even in daylight) would be a useful companion.

Intermittent issues can be so maddening. Anything the doctor can't catch in the act is hard to treat.
Click to expand...
This is my second go round with this noise.

He sent the car to a local shop before I ever looked at it. They claimed to have pulled the rear brakes apart to look for any issues and found nothing (interesting note - I discovered they didn’t do a thing. Rich’s shop painted the steel wheels on the car before selling it to him. There was paint all over the lug nuts , studs and axle snub and no witness marks or broken paint on the lugs or studs - the shop charged him $400 for nothing…..this is a 5 star rated shop owned by a Volvo enthusiast, I’ve been doing a lot of their RWD “come backs” lately)

He brought it to me and couldn’t duplicate the noise, I did a quick check and never found anything.

I got a text from him a week later claiming he found one of the mudflaps was loose and had evidence of dragging. He got it reattached, and all was good for a few weeks.

The noise came back and apparently didn’t go away. He had the car flatbeded back to his house. I feel like if there was something stuck under the car it would have been noticed during loading.

I’m gonna keep driving it throughout the week. I really hope it does it for me.
 
Toybox said:
A noise or vibration can be telegraphed through the car very effectively. Sure, location often correlates... but the mere fact that it sounds like it's in the rear doesn't provide absolute proof that it is.
Click to expand...

This is my first thought whenever I read that a sound is coming from a specific part of the car.
 
So it still has not duplicated the noise for me, 150 miles in.

I did bring my IR gun for the ride today. The left rear rotor is consistently 15% hotter than the right.

My only theory at this point is a slightly (or occasionally more than slightly) sticky caliper and a slightly worn wheel bearing. Left right steering and movement of the car jogs the axle enough to knock the pads back because of the play in the bearing. Going to replace bearings, pads, rotors and calipers in the back and hope it never comes back. Might go with the RW131R style rear bearing like I tried on the rally car.
 
Last edited:
pat244ti said:
Left right steering and movement of the car jogs the axle enough to knock the pads back because of the play in the bearing. Going to replace bearings, pads, rotors and calipers in the back and hope it never comes back.
Click to expand...

Awesome! Then he'll have the opportunity to hear a noise that can no longer be swished away! ;-)


(but seriously... good luck.)
 
When mikeP installed a LSD into an axle for me, we found that the carrier bearings on the LSD had spun (some light marks on the surface where the bearings are pressed on). I never drove the LSD prior, so I don't know if it made noise, but I"m guessing not.

He knurled the surface with a punch and pressed on new bearings and everything worked as expected, never any weird noises.

At one point, I think on a prior diff install, I had noticed the races for the rear wheel bearings spin easily in the housing. They were not press fit like the front hub races. I think that was normal...and they wouldn't spin when the axles were installed. But yet another hidden thing that could possibly maybe be making a weird noise once in a while....but probably not.
 
You must log in or register to reply here.
Back
Top