Rear Wheel Rolling Resistance & Stupidity

[rwantin]

Hi,

I'm admittedly not around here much, so sheepishly posting this request for some guidance. I'm a little stumped and there's WAY too many knowledgeable people here to not seek a little insight.

I have a Mark IV with a Ford 8.8/Moser axles and a 3.31 gear. Car only has a few hundred miles on it and I am still sorting some things.

I noticed, either in pushing it in the garage or even creeping the car in the driveway, it doesn't roll as freely as it should. The resistance is light, it is like it stops just before it should. You know, like rolling another foot. Naturally, I assumed the parking brake. The lever action is fine and seems to fully disengage. I crawled under the middle of the car - cables at the lever assembly seemed to have a little slack, but just for good measure backed off a bit. I jacked up the rear of the car. I can turn the wheels by hand but there seems to be more resistance than there should be. I removed the wheels (more on that later), disconnected the parking brake cables at the caliper (not sure what calipers these are but they have the pivoting arm at the top). Still resistance. Pad space seemed okay but even unbolted the calipers. Same. The axles turn, just not very freely.

Maybe this is normal? Doesn't seem like it should be? Not broken in yet?

Now for the stupidity part. The spinner adapters on the right-side of the car are left-hand threaded. I KNEW this, and in fact, even had the wheels off once before. But I was so focused at the the task at hand I somehow forgot this very important fact and broke the spinner adapter. Of course they are out of stock (F/F part #15374), and after researching the hell out of it, still can't find the source or who makes it. I took it to a sage local welder but already knew the answer - he declined. It is effectively a bolt and don't want that thing flying off at speed. Any thoughts on a replacement most welcome.

Thanks all (in advance).

Pics because we all like pics.

151384
151383

[Jeff Kleiner]

They are produced overseas to FFR's specs using FFR's tooling. I don't think you're going to find them anywhere else. A "want to buy" in the forum classifieds might turn up a spare that someone has for one reason or another.

Jeff

[egchewy79]

maybe the resistance is just the fluid in your gearbox?
it's not the parking brake if you feel this even with the cable disengaged and the calipers off.
regarding your spinner, oof. not sure where to get a replacement. what's that snap ring for? I don't recall seeing one on my spinner hub attachment.

[ggunter]

To check for brake drag roll up on a very slight incline and stop. Take your foot off the brake and see if it freely rolls backward. It should. If you have a brake dragging it will be much hotter to the touch then the rest of the wheels.

[rwantin]

They are produced overseas to FFR's specs using FFR's tooling. I don't think you're going to find them anywhere else. A "want to buy" in the forum classifieds might turn up a spare that someone has for one reason or another.

Jeff

Thank you sir, and that was what I was afraid of. :(

[rwantin]

maybe the resistance is just the fluid in your gearbox?
it's not the parking brake if you feel this even with the cable disengaged and the calipers off.
regarding your spinner, oof. not sure where to get a replacement. what's that snap ring for? I don't recall seeing one on my spinner hub attachment.

Thank you - it would be nice if it was just that, and maybe it is. I'm a little OCD and a perfectionist. The snap ring was inside the hub in its own groove - and it's hella fun to get out. :)

[rwantin]

To check for brake drag roll up on a very slight incline and stop. Take your foot off the brake and see if it freely rolls backward. It should. If you have a brake dragging it will be much hotter to the touch then the rest of the wheels.

Thanks! I checked for any abnormal temp on a little run, didn't notice anything. I am pretty sure the weight of the car would overcome the resistance even on a slight incline, the resistance is that light. Maybe I'm just overthinking this.

[Railroad]

If you have not had an alignment, your toe or thrust angle may be so severe it is creating tire scrub. JAWAG

[Avalanche325]

Your are turning the axles, rear end gears, driveshaft , and the transmission output shaft. There are axle, pinion and transmission rear seals that all rub. It is nothing like spinning a front wheel. There is a considerable amount of friction. The drivetrain takes about 15% of your horsepower. Also, as far as rolling, the car weighs 2150lbs so has less momentum than most cars. And add in wide sticky tires.

Are you hearing any abnormal noises? I had a pinion bearing go bad and could hear it easily even with my louder than most car.

[GWL]

All during my build the alignment was way off and it took a bit to move the car around the shop. Once aligned it moved easily. Now, I say easily because it was a bear before alignment. ��

George

[rwantin]

Your are turning the axles, rear end gears, driveshaft , and the transmission output shaft. There are axle, pinion and transmission rear seals that all rub. It is nothing like spinning a front wheel. There is a considerable amount of friction. The drivetrain takes about 15% of your horsepower. Also, as far as rolling, the car weighs 2150lbs so has less momentum than most cars. And add in wide sticky tires.

Are you hearing any abnormal noises? I had a pinion bearing go bad and could hear it easily even with my louder than most car.

Thank you. No abnormal noises, which is good. What you say makes a lot of sense. I've been working on vehicles forever and it just seemed a bit odd or even unusual. BUT, the context definitely makes even more sense here - very light car and very sticky tires. Maybe I just haven't really encountered this before. I'm far from a master mechanic, but am excellent at finding problems that don't exist, and even creating them (say, busting the adapter in the process).

[RoadRacer]

Don't feel bad.. I once convinced myself to put a set of spinner adapters on the wrong sides of the car and lost a wheel at speed on a circuit. That may be stupider. I had to go find my wheel in a corn field beside the track :D

[rich grsc]

Your are turning the axles, rear end gears, driveshaft , and the transmission output shaft. There are axle, pinion and transmission rear seals that all rub. It is nothing like spinning a front wheel. There is a considerable amount of friction. The drivetrain takes about 15% of your horsepower. Also, as far as rolling, the car weighs 2150lbs so has less momentum than most cars. And add in wide sticky tires.

Are you hearing any abnormal noises? I had a pinion bearing go bad and could hear it easily even with my louder than most car.

This 100% on the money. There is NOTHING wrong with your car, go try pushing your daily driver

[rwantin]

Don't feel bad.. I once convinced myself to put a set of spinner adapters on the wrong sides of the car and lost a wheel at speed on a circuit. That may be stupider. I had to go find my wheel in a corn field beside the track :D

Ouch! Okay, that does make me feel a bit better and I thank you for that. :eek:

[ggunter]

Never call yourself stupid, there is not a person in this world who came out of their mothers womb with brain surgery capability. They LEARNED it like everything else in life. While all of us have varying capabilities we learned every bit of it. So never sell yourself short. If you don't know, seek knowledge. This forum has a vast supply of knowledge form some very talented people who are more then ready to share it with you. Make it fun:)

[Papa]

Resistance could be pre-load on the pinion.


https://www.youtube.com/watch?v=8APYO2sZyJU

[JohnK]

Don't feel bad.. I once convinced myself to put a set of spinner adapters on the wrong sides of the car and lost a wheel at speed on a circuit. That may be stupider. I had to go find my wheel in a corn field beside the track :D

OK, now that's funny! :D

[Avalanche325]

The preload is only around 25 inch pounds. The torque wrench to measure it looks like a toy. It does take a big breaker bar and almost a nose bleed to get the crush washer set though.

[David Hodgkins]

I got nuthin'...

But I LOVE that Green Color!!!

:)

[Papa]

The preload is only around 25 inch pounds. The torque wrench to measure it looks like a toy. It does take a big breaker bar and almost a nose bleed to get the crush washer set though.

My comment could have been a bit more clear, but I was suggesting perhaps the pre-load was way over spec.

[Avalanche325]

My comment could have been a bit more clear, but I was suggesting perhaps the pre-load was way over spec.

Got it. When my bearing went bad and I disconnected the driveshaft and turned the pinion flange, 1/2 turn wasn't too bad, the other half I could barely turn. It felt like I had square bearings.

I'll add that I had one axle seal leak and the differential cover leaked from the factory day one. So the pros don't always get it right.

[Walt]

I broke 3 of mine on the front before I figured out the problem. I had a friend weld them , I've had no problem with them coming apart after fixed , I would ask someone else to weld, there is not any load on these they just hold the spinner and nut covers on.

[JohnK]

I broke 3 of mine on the front before I figured out the problem. I had a friend weld them , I've had no problem with them coming apart after fixed , I would ask someone else to weld, there is not any load on these they just hold the spinner and nut covers on.

What was the problem that was causing them to break?

[rwantin]

I broke 3 of mine on the front before I figured out the problem. I had a friend weld them , I've had no problem with them coming apart after fixed , I would ask someone else to weld, there is not any load on these they just hold the spinner and nut covers on.

This is good to hear on the no problem. I did take it to a sage local welder the other day, even brought the spinner with me and explained the no-load, but he still politely declined. I’ll check other options.

[rwantin]

What was the problem that was causing them to break?

In my case it was a brain fart in that the right-hand side of the car has left-handed thread spinners. Insert D’Oh here.

[Bob Cowan]

Hi,
I removed the wheels (more on that later), disconnected the parking brake cables at the caliper (not sure what calipers these are but they have the pivoting arm at the top). Still resistance. Pad space seemed okay but even unbolted the calipers. Same. The axles turn, just not very freely.


Stock brake calipers have a self adjusting screw type mechanism for the parking brake. Taking the slack out of the cable will not take the slack out of the pads.

Take the calipers off the rotors. Was there a lot of resistance to that? Were they hard to remove? If so, then use a caliper tool to unscrew the pads about 1 turn or so.

[Norm B]

The resistance you're feeling is perfectly normal and the fact that it felt the same with the callipers removed proved the brakes aren't dragging. In addition to the preload drag Papa mentioned, there is viscous drag from the gear oil in the housing. Try moving a paint stick through that oil and you'll get an idea of the resistance. Each tooth on the crown gear is going to act like a paddle in the oil when moving at slow speed. At high speed the oil cavitates around the gear and the resistance is less. As you slow to a stop, the cavitation goes away and the resistance increases substantially.
The reason it feels different rolling to a stop is you have a large differential in a light weight car. The normal drag in the drivetrain will slow a 2200lb car noticeably quicker than a 3400lb car. The old F=MA situation.

Norm

[rwantin]

Stock brake calipers have a self adjusting screw type mechanism for the parking brake. Taking the slack out of the cable will not take the slack out of the pads.

Take the calipers off the rotors. Was there a lot of resistance to that? Were they hard to remove? If so, then use a caliper tool to unscrew the pads about 1 turn or so.

Thank you, the calipers were not overly difficult to remove or replace, so I think spacing/clearance was about right. I forgot about the Ford screw in - might be a handy tool to have around.

[rwantin]

The resistance you're feeling is perfectly normal and the fact that it felt the same with the callipers removed proved the brakes aren't dragging. In addition to the preload drag Papa mentioned, there is viscous drag from the gear oil in the housing. Try moving a paint stick through that oil and you'll get an idea of the resistance. Each tooth on the crown gear is going to act like a paddle in the oil when moving at slow speed. At high speed the oil cavitates around the gear and the resistance is less. As you slow to a stop, the cavitation goes away and the resistance increases substantially.
The reason it feels different rolling to a stop is you have a large differential in a light weight car. The normal drag in the drivetrain will slow a 2200lb car noticeably quicker than a 3400lb car. The old F=MA situation.

Norm

Thank you. The first order of business was to establish that the brakes weren't dragging, so I had that going for me at least.

This has been a very educational endeavor. I almost forgot what a great group this is.

[rwantin]

I got nuthin'...

But I LOVE that Green Color!!!

:)

This kinda made my day, thank you. Here's the kicker - this is my second Cobra. The first is in my avatar. I sold that to a friend and spent two years looking for something else when I finally realized the only thing that can replace a Cobra and that experience is another Cobra. I loved the first car/color so much the second is the EXACT SAME color (Jaguar Racing Green HGZ) just no stripes and bumpers this go around.

[johnnybgoode]

Hi,

I'm admittedly not around here much, so sheepishly posting this request for some guidance. I'm a little stumped and there's WAY too many knowledgeable people here to not seek a little insight.

I have a Mark IV with a Ford 8.8/Moser axles and a 3.31 gear. Car only has a few hundred miles on it and I am still sorting some things.

I noticed, either in pushing it in the garage or even creeping the car in the driveway, it doesn't roll as freely as it should. The resistance is light, it is like it stops just before it should. You know, like rolling another foot. Naturally, I assumed the parking brake. The lever action is fine and seems to fully disengage. I crawled under the middle of the car - cables at the lever assembly seemed to have a little slack, but just for good measure backed off a bit. I jacked up the rear of the car. I can turn the wheels by hand but there seems to be more resistance than there should be. I removed the wheels (more on that later), disconnected the parking brake cables at the caliper (not sure what calipers these are but they have the pivoting arm at the top). Still resistance. Pad space seemed okay but even unbolted the calipers. Same. The axles turn, just not very freely.

Maybe this is normal? Doesn't seem like it should be? Not broken in yet?

Now for the stupidity part. The spinner adapters on the right-side of the car are left-hand threaded. I KNEW this, and in fact, even had the wheels off once before. But I was so focused at the the task at hand I somehow forgot this very important fact and broke the spinner adapter. Of course they are out of stock (F/F part #15374), and after researching the hell out of it, still can't find the source or who makes it. I took it to a sage local welder but already knew the answer - he declined. It is effectively a bolt and don't want that thing flying off at speed. Any thoughts on a replacement most welcome.

Thanks all (in advance).

Pics because we all like pics.

151384
151383

A couple of thoughts you might want to try. My rear wheels are difficult to turn by hand as well but the roadster will roll down the driveway quite easily in neutral with the parking brake off. If your's will as well you are probably good to go.

You also may be able to glue your spinner back together with some JB Weld reinforced with strips of fiberglass cloth on the inside? Probably not a great long-term solution but might get you by until you can source a replacement.

My 2 cents for what it is worth. Good Luck. Scott

[Walt]

What was the problem that was causing them to break?

I have mustang hubs on the front and when I tightened the lug nuts it would break the back rim off of them, I ended up putting spacers under the wheels on lug bolts and have had no issues since.

[rwantin]

You guys are the freaking best. Can't thank you enough. And someone has a spare hub adapter they're sending my way. I've always done what I could for fellow gearheads (and for that matter, motorcyclists), some good karma appears to be heading back my way. Or something like that.

Thanks again.

[NC Cobra]

Beautiful looking car. Big fan of the BRG myself, although mine has a bit more blue in it. As we said at my alma mater, Go Green!

[kato]

Beautiful looking car. Big fan of the BRG myself, although mine has a bit more blue in it. As we said at my alma mater, Go Green!

The easiest way to remember what direction for the spinners/knock offs for me is Off to the front right or left sides its off to the front I believe this is true for all knock offs

[rwantin]

The easiest way to remember what direction for the spinners/knock offs for me is Off to the front right or left sides its off to the front I believe this is true for all knock offs

The sad thing is I actually knew this, I had a few old British cars and even had the wheels off the Cobra once before. Total brain fart.

HUGE thank you to mburger (Mark), who sent me a spare adapter, which I received yesterday. Again, there are some really good humans in this group.