Front wheel bearing preload.

[ricko1966]

Next time one of you that is really picky about front bearing preload and is using the rotund tool, please P.M. me. I have a math problem for you,and if I am right it will make your setup way easier in the future.

[Rick the Quick]

Hey ricko, as a matter of fact I don't have the Ford Rotunda Tool but I am also thinking about servicing the front wheel bearings. Does your information pertain to this job if I don't have the tool?

[ricko1966]

Yes sir. Many engines I have built required me checking deck height using clay or solder,some have had crankshaft end play that had to be set with shims,rearends and transmissions I have built had to have clearances set with shims. I set them up with way too much clearance and for example with a crank if I want .005 end play and I set it up with .020 in shim check my end play and say I have .015 I know I need .010 more shim. I have put all my festies back together with the shim I took out and have not had a problem,specs on tapered roller bearings are really tight provided they were made to spec. which is why you don't want the cheapest ones available. Now it is my opinion that the turning resistance you are measuring with the ford tool would be the same or super close if we just knew the preload measurement instead of turning resistance. So if someone initially set one up with .050 in shim and had .010 clearance and say it ended up needing .062 shim to be right now we know .060 would have been zero clearance .002 is the preload. If we know .002 is the preload now it is simple to set them with clay and math,solder and some math,or a dial indicator and some math. All my numbers were pulled out of thin air just to show the math.

[Rick the Quick]

Okay it all makes sense. I have never had front bearing failure on any of my Festivas. I have taken them apart and cleaned, inspected and repacked the bearings and reused the shims that came with each side and never had a problem. Building/shimming a bare knuckle would be another story. You obviously need to have a decent shim selection to begin with and as far as the Ford Rotunda tool goes, I don't have one. I would buy one if I see one at the right price. When I hear they sell for $125-$175 I am not interested. I don't see why I could not make one. Then I would need to buy an inch pound torque wrench, something I don't have. If I ever have the opportunity to use the Rotunda tool I will try to figure out the preload in thousands of an inch and I will post it here. I use a good old fashioned (cheap) fish scale for adjusting the rear hub bearings. It's always worked fine.

[ricko1966]

I like your fish scale idea. And as far as needing a decent shim selection I do not think that would be necessary.1 thickest shim. assemble, check clearance , do the math and order the appropriate shim. or even have just a few thick shims to surface down to the needed thickness.after you establish how thick it needs to be.

Okay it all makes sense. I have never had front bearing failure on any of my Festivas. I have taken them apart and cleaned, inspected and repacked the bearings and reused the shims that came with each side and never had a problem. Building/shimming a bare knuckle would be another story. You obviously need to have a decent shim selection to begin with and as far as the Ford Rotunda tool goes, I don't have one. I would buy one if I see one at the right price. When I hear they sell for $125-$175 I am not interested. I don't see why I could not make one. Then I would need to buy an inch pound torque wrench, something I don't have. If I ever have the opportunity to use the Rotunda tool I will try to figure out the preload in thousands of an inch and I will post it here. I use a good old fashioned (cheap) fish scale for adjusting the rear hub bearings. It's always worked fine.

[WmWatt]

I paint the shim number on the knuckle so they don't get mixed up. Last Iheard they come in a set of 32 sizes. Were available through Kia dealerships.

[ricko1966]

Thanksgiving just came and went. Meant to thank you sir for the canola oil and thinner idea. It was delicious on the salad and I sprayed the rest on some lt-1 heads and some cranks I needed to protect.

I paint the shim number on the knuckle so they don't get mixed up. Last Iheard they come in a set of 32 sizes. Were available through Kia dealerships.

[skeeters_keeper]

The bearing drag/preload relationship is not linear. If we knew it took .001" interference to create 5inlbs force that could be useful, if the measurements could be accurate enough, but clay would be too soft - a hard solder might work, if it's spread evenly in a disc or at least 3 points around the circumference.

.0005" increases drag by ~2-3in lbs when close the the desire range (I aim for 5-8in lbs). Just surface grind .0005" at a time till it's right. Pretty easy and measuring drag is the most direct way to check preload on tapered bearings. FWIW I've never had a knuckle fall in that range with the factory spacer, but for a daily driver the stock spacer is more than likely going to be fine.

The tools are available fairly inexpensively through TFS: http://www.thefestivastore.com/item/...selection-tool

[ricko1966]

Thank you , but not quite what I was getting at sorry I confused you I wasn't thinking of using solder or clay to obtain preload only to find zero using solder or clay in place of the shim and then do the math after measuring the crushed clay or solder ring but thought the best option was use a thick shim check lateral movement and do the math to find zero then use the appropriate shim to give say .002 preload.I haven't been that worried about it I just reuse my factory shims in my cars but they are just dds. Now that I know that a specific preload measurement won't work, I can quit thinking about it. But seriously I think at least for a dd there would have to be a number that works,if you know zero is going to be to loose and you know .010 is going to be to tight then we'd need to see if .005 is to loose and .009 is to tight.soon we would have to have a number that at least gets you in the ball park on the first try. Like when shimming end play I don't just keep taking things apart changing shims and put it back together to recheck and repeat. I put it together too loose so I know how far out of spec I am on my first check, then I will have the right shims the very next time I assemble it.Maybe in this instance it wouldn't be ideal on the second check but should be real close. Sorry, I sometimes overthink things.QUOTE=skeeters_keeper;759807]The bearing drag/preload relationship is not linear. If we knew it took .001" interference to create 5inlbs force that could be useful, if the measurements could be accurate enough, but clay would be too soft - a hard solder might work, if it's spread evenly in a disc or at least 3 points around the circumference.

.0005" increases drag by ~2-3in lbs when close the the desire range (I aim for 5-8in lbs). Just surface grind .0005" at a time till it's right. Pretty easy and measuring drag is the most direct way to check preload on tapered bearings. FWIW I've never had a knuckle fall in that range with the factory spacer, but for a daily driver the stock spacer is more than likely going to be fine.

The tools are available fairly inexpensively through TFS: http://www.thefestivastore.com/item/...selection-tool[/QUOTE]