Clunk In Front: Bad Front Disc Rotor or Bearings? Or....

[vamram]

Having an issue w/the front end on my '73 Super and I'm wondering if this could be an issue w/the rotor or the bearings. The car came w/front discs installed and they've been great w/zero issues over the year I've had it on the road. Still stop on a dime, lots of pad left. I do not know what brand they are however.

The car's developed a clunk on bad road lately, no shimmy though, just a clunk over bumps which I've experienced previously w/bad ball joints. Ball joints are good, i raised the the front today and checked them. But there's play when I grab the tire and move it noon-6. Normally this would be the bearings needing adjustment but there's no noise or grinding as you get w/bad bearings. I tightened them per Bentley, but no difference. I can see the rotor moving on the spindle, there's no play in the mounting bracket. Are these bearings shot? Is the rotor shot? Or Is it normal for a rotor to have some play like this?

Thanks!
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Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
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[VW_Jimbo]

Not normal. What happens at the 3 & 9 o’clock positions? Same
Or different?

You looked at the threads of the axle stub and the nut really closely - right?
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[vamram]

Same, Jimbo.
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[vamram]

I should've added that it's like this on both sides, though more notable on the passenger side.
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[VW_Jimbo]

Have you tried adjusting the free play at the bearings again?
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[vamram]

I did on the passenger side. I'll run thru both sides tomorrow to confirm. What if there's still play after following the procedure per Bentley? Replace the bearings?
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[VW_Jimbo]

[viiking]

I'd say bearings have started to fail or the stub axle is worn.

Have you changed the bearings at all? I believe the drum and disc brake bearings are not normally the same so could the OP have used the wrong bearings?
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[vamram]

[bnam]

I think there would be some play at 12and 6 - the suspension is mounted on rubber bushings at the control rod and the top of the strut.

Clunking can come from many places. I’ve had one clunking go away when I replaced the rubber bushing for the sway bar on the control rod.
[/i]
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1971 1302LS Convertible (RHD) owned since '74
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1965 Karmann Ghia Coupe - under restoration
1966 Fiat 1500 Cabrio (with 1600 Twin cam)
1952 Citroen TA 11BL

[vamram]

[Tim Donahoe]

My bet is on wheel bearings. You’ve adjusted them properly, so, unless you’re tie rod ends or ball joints have failed too soon, that’s my best guess.

Tim
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Let's do the Time Warp again!

Richard O'Brien

[VW_Jimbo]

I have never had bearing go “clunk”, but I would not rule anything out. Go through and inspect. Typically a clunk is a bolted on component. That attachment is what makes the deep metal resonate. I would be looking at a strut mount or the attachment at the lower portion of the strut. Not sure what style you have. Seen only a few get loose some how.

The bearings could make a “clunk” noise but they would need to slide against the seal wall or the axle nut. Either way, that means the bearings are loose for some reason.

I am trying to recall, but didn’t EMPI, at some point send out the wrong size bearings with their front disc kits? Might be worth a call.

Remembered that, or so I think I did. Thought you should know, so you could look into it!

Good luck Victor!
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[AutoMechanic]

Check the condition of the bearings clean them and repack them before replacing. They may just need conditioned good. Especially if they aren’t scored up.

[vamram]

I think the bearings are shot. If I follow Rob & Dave's procedure http://www.vw-resource.com/whl-brng.html there's lots of noon-6 a.m. play, way more than normal. I did find one video on youtube that set the bearings w/front discs by tightening the nut until you could not turn the rotor, then back out 1/4 turn. Even following this method, which I've not read elsehwere - tightening down the nut until the wheel basically locks - I still end up w/unacceptable play noon-6. This youtube method was on an airkweld site https://www.youtube.com/watch?v=pyl5YT6kDbI showing a custom front end w/non-stock disc rotors, so I guess it may not apply. Skip to the 58 second mark - everything up to that point is fluff. I'm also trying to rule out movement of the strut spring.

Time for new bearings I guess....These are stock spindles. Will stock drum bearings work? Or should I buy ones for say a '73 Ghia?

Víctor
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[vamram]

More confusion. Reading the Haynes' Volkswagen Super Beetle 1972 On and Basic Beetle 1970 On, page 169:

"...The nut should be backed off until the axial play is between 0.03-0.12mm (.001-.006 inch) at the spindle...this...can result in some quite noticeable rock at the outer rim of the wheel....It is nevertheless correct...."

So...which is it?? Some Play? Or Airkweld's method? Or new bearings??
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[viiking]

Regarding just the bearings, the problem is that you unfortunately don't exactly know what brand the disc set-up is. Why use the Bentley if it isn't a stock VW?

Every car I have worked on uses the similar principle to tighten up the bearing, then return back until the cotter pin goes in the next loose hole. It is to ensure the bearing is not too tight. Of course if you have the correct tools then use the axial play measurement that the equipment manufacturer specifies.

Take a photo and post it here to see if we can help identify it. If it is a stock VW calliper you would most likely have a 2 pin, pad-retaining pin setup. (One pin was available as well but much earlier e.g. 1968 for Euro spec). Also do you know the bearing numbers on the inner and outer bearing?

According to OACDP and my previous comments, the bearings for stock VW discs and drums are not necessarily the same. Ditto the spindle. The only way to make sure is to measure the ID of the bearing and the OD of the spindle.

Then you have to measure the ID of the rotor and the OD of the bearing as well. Getting complicated. This will tell you whether the bearings are no good or even that the rotor inner surfaces also may have worn.

As far as any hard knock is concerned, I assume you have checked things like all the bolts are tight and there is no looseness/up/down movement in the suspension components. Have you tried to lift the wheel off the ground slightly and use a lever such as a 4x2 under the wheel to lift up and down to see if you can see any movement in the suspension?

Finally the only other things that comes to mind is that the spreader spring on the disc retaining pin(s) is weak allowing the pad to move up and down more than normal. These should be (but rarely are) changes with new pads. I would assume this would show as visible marks on the pads where there may be metal to metal contact. Also make sure the piston retaining plate is in place. However I don't think it would give such a loud knock you are experiencing.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[H2OSB]

If it were a watercooled vw, I would suggest the upper strut mounts. They will clunk under the right circumstances when worn, but I never experienced that on a Super. Might not hurt to check, though.

H2OSB
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[vamram]

Interesting afternoon. Here are a couple of pictures of the caliper and the rotor. It's a 2-pin caliper, like Ghia's I guess. Stock Super spindle w/the mounting adapter bracket. I had not seen Viiking's comments above so no measurements were taken.

Here you may be able to see/hear the clunk. If I tighten the nut anymore the rotor would almost require two hands to turn.

Link
. I'm still leaning towards shot bearings...except for the lack of bad-bearing sounds...

And lo-and-behold I found the source of the Klunk. You'll love this, Viiking.

I've owned 4 Super Beetles and have never had this happen The cap is off of the strut enclosure. Threads are fine, i was able to get it back on w/out removing the strut and shockingly the insert did not burst or bend. Drove it and no more clunk, car drives completely normally. Now about those bearings....
_________________
"Men are qualified for civil liberty in exact proportion to their disposition
to put moral chains upon their own appetites. -Edmund Burke
“If something cannot go on forever, it will stop.”
Stop Russian-Soviet Aggression!!

'74 Super 9/16 - present, in refurb process.
'73 Super - 6/18 - Present - Daily Driver!
'75 Super Le Grande...languishing since 2022.
Click to view image
Save the Supers!!

[viiking]

Eureka! Glad you found it.

Thanks for letting us all know. Too many times people have a problem, then disappear without ever giving the benefit of the experience to others who may in the future be using the search function for the same thing.

I'd leave the bearings for now. You want to tackle one solution at a time to make sure the original issue goes away.Fix the thing that may have broken last.

Just looking at your first picture. Not sure if it is an illusion or not but it looks like the pads are only touching the outer part of the rotor going by the scratch marks. There is a "worn section" on the outer but not on the inner near the hub itself. Are you sure your pads are sitting flat?

Or is it just the picture?
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3