I have a strange noise which appears intermittently on quite hard right-hand cornering, typically if going around a roundabout reasonably hard. It’s a sort of scuffing/scraping noise, which goes away as soon as the car is travelling straight again. The brakes don’t have to be on for the noise to sound.
The rears are the standard XK140 drums with the original (later type) geared adjuster. All is reassembled with new components - retracting springs, beehive springs, cylinder, hand brake parts, shoes and drums.
I have recently changed the drums for a pair of Alfins, with their recommended Ferodo shoe lining. The brakes work fine and are not getting hot. Removal of the drum reveals a nice even pattern of contact on the shoes, although the wear pattern appears to be more visible on the inboard edge of the shoes, nearer to the backplate, as if this part of the shoe is contacting more than the outer edge. I have checked very carefully to ensure that the beehive spings are holding things down as they should, and all is well. Unfortunately I don’t remember hearing this noise during the 200 miles I drove the car with the old (but new!) shoes and the cast-iron drum, but that’s not to say it wasn’t there.
Any thoughts? I’ve been over it really carefully, but as the Ferodo shoes are a closer fit to the drums than the old Barratt’s shoes were with the cast-iron, I’m pretty sure nothing’s assembled incorrectly. Maybe this will settle with time, as the shoes bed in. I’m just wondering why it’s only on corners as the axle is fully rebuilt with new bearings etc. Maybe it’s the tyre?
I don’t see how the brake alignment could be affected by cornering. Check the insides of the inner fenders, fenders and skirts for rubbing marks from the tires and see if you find anything.
Thanks Mike, those were my thoughts too. The axle has all new bearings, driveshafts etc. so I don’t see how anything could be moving with respect to the hub etc. I have had a good check around but another thorough examination won’t hurt.
The entire axle could be moving side-to-side in reaction to side forces when going around a corner. The leaf springs are the only things that center the rear axle and if the bushings are worn it could shift.
Oh, for a Panhard rod!
It’s all brand new, Mike, 400 miles since complete restoration.
I was under it again today and noticed that one of the screws that clamp the brake line around the rear axle had rotated around the axle casing, and the end of the thread has been contacting and wearing against the top section of the telescopic damper. I’ve readjusted that and will see if the noise is still there tomorrow.
I had the same-ish noise. Turned out my new brake shoes were just ever-so-slightly wide. I took 1/32" off of the width (on the outside/drum side) on a grinder, no more noise. 1953 XK120FHC, factory drums and brakes. The new shoes seemed to be the same width as the old ones, but maybe a build-up (loss) of tolerances between the new shoes and the new linings. When I looked closely I could see faint evidence of the edge of the shoe rubbing against the drum.
That’s also a possibility. As I said, I don’t think the noise was there with the ‘old’ (not very) shoes/drums, but appeared after I’d fitted the Alfin parts. Something else to investigate, thanks for the tip!
On a completely different car many years ago, I experienced the same noise under the same circumstances. It was caused by a loose wheel bearing. Your bearings are reportedly new, but are they adjusted correctly?
That might be worth a look, Bob. It still did it today, so it wasn’t the errant screw thread. I took off the O/S drum and discovered that the shoe itself doesn’t seem to have been touching the drum, but the radius in the corner of the drum is polished so I think the shoe lining material might be rubbing on this radius under cornering. I’ve made a slight chamfer on the edge just to check.
Failing that I’ll investigate the bearing. There is no movement whatsoever of the hub or driveshaft, and as the noise is not there 99.9% of the time, I don’t want to go pulling the hub off the taper again. However if needs must…
Finally sorted this. None of the above stopped the noise, which continued to annoy me (although not particularly loud) on the weekend’s trip to the Donington Historic races, where the car was on the XK Club stand.
So, this morning I was all set to check bearing endfloat and tear into the bearing, fearing the worst. Having wedged one side, the dial gauge gave me a reading of 5-6 thou: to be sure, I swapped the wedge to the other side, but got the same reading. Puzzling.
Then I spotted a new thin line on the offside backplate where the outer edge of the drum had been rubbing a bit more with the extra 200 miles driven. A straight edge and engineer’s rule revealed that the top of this backplate had a slight bend in it, leaning in 4mm towards the drum. This hadn’t shown up with the standard cast iron drum, which had a rounded edge - but the Alfin drums are more squared off due to the steel liner. A little precision adjustment of the backplate with a blunt instrument has fixed it.
Did that fix it or just take away the noise? There had to be some movement in the system to allow for quiet running on the straight, but scraping when under load on a turn. Just asking.
I’m going to say it fixed it, Bob, as I can’t see any other problems.
The worn paint surface on the backplate only appeared after around 700 miles. It is a thin arc of primer now showing through the gloss black with a length of about 2.5". The axle endfloat is correct at 0.006" with one end wedged and using two large screwdrivers on the opposing flange, so I think it is literally the endfloat that was allowing the contact with the bent section of the backplate. It’s never been a loud noise - you really have to listen for it, but I knew it was there. Like all rogue noises, once heard, you always hear it.
Measuring the gap between backplate edge and the fins on the drums gives a constant 62mm all the way around both backplates until I get to the top 6-8" of the offside one. At some point in its life this has received a whack, I can’t imagine how - most likely whilst not fitted to the car, as both rear backplates are used replacements. The gap was around 56mm here, but I’ve got it back to 59mm. The steel plate is so thick that any further correction is impossible without dismantling that side of the axle, which I don’t want to do just now - I do have the correct Churchill hub puller but that’s a job to do when necessary. The only issue I can think of might be a slightly odd brake shoe wear pattern, with more wear on the inboard edge as the beehive spring holds the shoe against that bent section, but the difference is minimal and I have no idea how far down the backplate the bent area extends. It looks like it may just be the lip of the backplate. I’ll keep an eye on it.