Grinding Calipers

[PixelWrangler]

After working through this I believe I have my answer, but thought I would start a thread for others considering the same dilemma. Even though I searched extensively. I couldn’t find a thread that covered my exact situation, doesn’t mean there isn’t one, I just didn’t find it after looking for months. With the input of the great ones on the Mud forum, maybe some alternative answers can be found.

The back story.

Last year I had the brakes switched over to discs front and back. 60 series knuckles and discs up front and Cadillac Eldorado in the back. It’s been a sweet setup so far. I had been lucky with the vintage alloy wheels that came with the rig in that they cleared the calipers and tie rod ends. But I only had the four and my mismatched spare hit the calipers, not good. Soooo… I decided I needed new feet for the old gal in addition to new shoes.

After researching for months here on Mud and with the various wheel suppliers, I finally pulled the trigger last April on a set of five wheels. I decided that the ProComp 15” Rock Crawler Series 52 Gloss Black Powder Wheel - 52-5883 with 2-1/2” back spacing would do the trick. 4 Wheel Parts seemed to have as good a price as anyone so I ordered through their website.

I had gone into their Compton store several times to talk to the guys and get as much info as I could. They were of limited help as they couldn’t entertain thoughts of making modifications like grinding the calipers a bit for clearance. I was reluctant to use a wheel spacer to achieve my goal.

After 2-1/2 months and many phone calls, I finally got the call that they had arrived in Compton. When I picked them up yesterday, I ordered up a set of 35” KM2’s to skin them with. They should arrive by next weekend from their Texas warehouse. Should be enough time to see what I have to deal with in getting them on the rig.

I pulled one of the rear tires first to see what I might be up against. OK, so they hit the outside edge of the caliper. I doesn’t look like much, but of course the wheel isn’t seated either. A tiny bit of light sneaking through between the caliper and the wheel.

You can see a bit of scuffing on the lower outside edge where the wheel was making contact.

Out comes the grinder. For the next hour and a half I’m grinding a bit, fitting the wheel seeing where it’s hitting, marking the area, grinding a bit more and repeat. I’m paranoid of taking too much off, I am talking about the integrity of the brakes on my daily driver after all. Finally, I get it down to where it’s clearing the wheel by about .019”. And this is where I am now. It might look like a lot, but there seems to be plenty of meat left on the caliper so I’m not too concerned, yet.

The questions I have now are, is .019” enough clearance? I would feel more comfortable with more, but am a little leery about taking too much off. The outer pads seem to be engaged mechanically rather than hydraulically, but I could be wrong. How much movement is there in the caliper while braking? I’m working solo on this so it’s hard to tell and perhaps there’s more movement when the rig is actually moving. This is stuff I just don’t know and would love to hear some thoughts from the pro’s.

 

[PixelWrangler]

The front is a different story of course with the 60 series disc brakes. There’s plenty of clearance for the tie rod ends.

Of course being a different caliper and much larger it hits in a different place. On the inside edge.

Again, here’s where the wheel is touching the caliper.

It doesn’t appear to be much, but again the wheel isn’t fully seated either. After about an hour of the same grind, fit, mark, repeat, it looks like this and it still isn’t clearing the caliper.

The lower edge clears by 1/8”, but the upper edge doesn’t as it rides 1/4” closer to the hub. I can’t tell for sure how much more it’ll take to clear, but I’m guessing much more than I would like. I’m really afraid of taking any more off of these, as they appear to have reservoirs that I could grind into, and maybe I’ve gone too far now. I don’t know what the wall thickness here is. That would be very bad.

So my conclusion is to just get the 1/4” wheel spacers as much as I didn’t want to go that route. I know many use them and have no issues. The question I have here is, are the lug bolts long enough as is with 1/4” spacers? I’m thinking probably and will undoubtedly run that way at first, but if the consensus is no, then I’ll source out a set to install after the new tires arrive. I’ve seen part numbers posted elsewhere, but if someone has those numbers handy maybe they could post them up here also for future reference.

Referring back to wheel spacers, months ago I bought a cheap pair from Summit Racing in anticipation of this dilemma.

But being set up for both 5 and 6 hole by 5.5, I don’t see how they can possibly be balanced. I wasn’t able to locate anything on Summits website with just the 6 x 5.5 pattern and a 4.25” center. I located a website that will build a set to your specifications, but they want $200 for a set of 4, almost what I paid for the wheels. Does anyone have any recommendations for a reasonable priced set? I would think a set should be available for closer to $100 given the popularity of the bolt pattern. I know I’ll find something, again it’s more for the future reference of others than for myself. Of course, I’ll be posting up anything I come up with.

Thanks for your help and input!

 

[71AZFJ]

I'm doing the exact same convertion now, and was worried about the problems your having. Please keep us posted.

 

[landcrusher909]

I'm doing the exact same convertion now, and was worried about the problems your having. Please keep us posted.

Same here I had a set of 16 in wagon wheels that came off a 1983 FJ40 I gave to my buddy they worked out perfect I might end up doing the same

 

[Spike Strip]

There are some spacers available that fit perfectly and are around $70, made of steel, made by either Gorilla or Mr. Gasket (can't remember...), but when I ran into this problem with my 60, when I installed larger, 4runner calipers, I just used the cheap summit ones as in your pic and no problems whatsoever. That was 3 years ago.

 

[71AZFJ]

The wheels I want, are the same ones PixelWrangler bought. Is this still a problem if the rim size was changed to a 16" rim ?

 

[Josie'sLandCruiser]

Hi All:

I have used 1/4 inch spacers without any issues.

You should not have to "clearance" (i.e. grind on) stock brake calipers if running wheels with close-to-OE backspacing.

Regards,

Alan

 

[PixelWrangler]

There are some spacers available that fit perfectly and are around $70, made of steel, made by either Gorilla or Mr. Gasket (can't remember...), but when I ran into this problem with my 60, when I installed larger, 4runner calipers, I just used the cheap summit ones as in your pic and no problems whatsoever. That was 3 years ago.

I checked the Gorilla and Mr. Gasket spacers, I didn't see a steel option only aluminum. But they at least have some "tighter" looking spacers. With what I have, I'm just concerned that there could be a bit of vibration from both the looseness of the spacer as well as it being off balance with more holes on one side than the other. Evidently your not experiencing any of that?

 

[PixelWrangler]

The wheels I want, are the same ones PixelWrangler bought. Is this still a problem if the rim size was changed to a 16" rim ?

Without using a spacer, I don't think a 16" wheel would make a difference for clearing the caliper. It's a matter of the angle that the wheel leaves the hub surface. The 60 series calipers are just a bit too big and too close to the hub. The Eldorado calipers in the rear would be no problem though with 16" wheels. I wish wheel makers would publish cross sections of their wheels with measurements so we could figure all of this s*** out before laying down the big bucks and committing to a particular wheel.

As I mentioned earlier, I considered 16" wheels briefly. Then I looked at the price difference with the tires. Currently 35x12.5 - 15" BFG KM2's from 4 Wheel Parts are $230 each. The same tire in 16" is $306 each. For the 5 tires I bought, that's a difference of $380 not including the taxes. My budget just wouldn't allow it.

 

[bikersmurf]

I've been running aluminum spacers like that for 20 years on front and 12+ years on rear. No problems with balance or other issues.

 

[3DAMAN!]

From looking at your pictures, you need to grind a lot more off!. They do not need to be polished.
If you had to run a weight on the inside of the wheel, it would not last 1 revolution.
Been there, done that. .019/.020?
Hell, a quarter inch might not be enough.
There is a lot of cast iron left on those calipers that could be removed if needed.
Quit fooling around and take a 4 inch grinder and grind 'em

 

[PixelWrangler]

Hi All:

I have used 1/4 inch spacers without any issues.

You should not have to "clearance" (i.e. grind on) stock brake calipers if running wheels with close-to-OE backspacing.

Regards,

Alan

Exactly what I found today. Did you need to install longer lug bolts?

 

[PixelWrangler]

I decided to see what the 1/4” spacers would do for me today. I had only ground the calipers on the passenger side, so the drivers side was untouched. With 1/4” spacers these wheels fit perfectly. Seems like there is plenty of space for the calipers.

Here’s the 60 series in the front, the wheel spins easily and it seems like there is at least 1/8” clearance. But look at how much thread there is on the lug bolts! At most there is 1/2”.

Here is the Eldorado caliper in the rear. Plenty of clearance. But there is only about 3/8” of bolt showing! The rotors in the rear evidently are an 1/8” thicker than the ones in the front.

They are also not attached to the axle, just floating there and held in place by the wheel and lug nuts. You can see in these photos that the rotor is also not centered and hits the pad on one side.

Is this usual for Eldorado rotors? I’m guessing these are Eldorado rotors but not certain. Seems like they should be bolted to the hub like the 60 series rotors are.

As far as the wheels, from what I know now, I would most likely not get them with 2-1/2” back spacing. The back spacing only helps with the tie rod end clearance, it does nothing for clearing the calipers. From what I understand 3-1/2” is the stock back spacing. The alloy wheels I’m currently running have 3-3/4” BS. They clear the tie rod ends, but it looks like most of my wheel weights have been knocked off.

If I were to order wheels now, with what I’ve found, I would probably get 3-1/2” back spacing and 1/4” spacers. That set up would clear both the tie rod ends as well as the calipers. And I wouldn’t have had to wait for 2-1/2 months as they are readily available. If I didn’t want my big fatties sticking out the side of the rig as much I might go with these Spidertrax 1-1/2” spacers and wheels with 4-1/2” back spacing.

That should give you tires that are set in about an 3/4” from what I’ll have with my set up. It would also give you plenty of clearance for the calipers and the tie rod ends. It would be the equivalent of a 3” back spaced wheel, with the additional benefit of clearing the calipers. You would also not have to install longer lug bolts like I will

So, I’ve got some decisions to make. I don’t like that my wheels will have such a wide stance and putting extra stress on the knuckle bearings as well as the lug bolts. I’m sure it will be very stable on the road, but I don’t like that the wheels will stick out the side of the rig so far though. I was figuring that I’d have to put on some rear fender flares and I’m OK with that, but I don’t like the look of the front fender flares. I’m surprised that I haven’t been stopped for not having the rear ones on as it is.

Decisions, decisions!

 

[PixelWrangler]

I've been running aluminum spacers like that for 20 years on front and 12+ years on rear. No problems with balance or other issues.

Good to know. Another vote for these spacers, guess I should relax a bit on that issue!

 

[camcruiser13]

I just ground mine down. I run 2.5 bs wheels same brand and everything as yours. Plenty of brake caliper to grind. Been running like that for several years no prob. I grounded mine down so I could take my spacers off.

 

[bikersmurf]

I don't need the spacers on the rear... I'm running them to make up for the thick drums that I've removed. When I converted to discs on the rear FF axle I mounted full sized Chevy Blazer rotors to the rear of the hubs. There are no issues with clearance with 3.5" back spaced white spoke rims.


In the front the clearance was close to stock Landcruiser calipers, and I'd rather not grind them unless necessary.

 

[PixelWrangler]

From looking at your pictures, you need to grind a lot more off!. They do not need to be polished.
If you had to run a weight on the inside of the wheel, it would not last 1 revolution.
Been there, done that. .019/.020?
Hell, a quarter inch might not be enough.
There is a lot of cast iron left on those calipers that could be removed if needed.
Quit fooling around and take a 4 inch grinder and grind 'em

The photos may not show it real well, but I've taken more than an 1/8" off of the corners of each caliper where it was hitting. 4" grinder is what I used. If I were to take another 1/4" off then the Eldorado caliper would break off as there is only a 1/4" of material left on the corner. The 60 series caliper I'm pretty certain doesn't have that much material left before I open up the reservoir chambers, I've cut pretty deep into that upper corner. I don't know for certain, but the little lump on the top surface I've cut into looks like it may shield a port that feeds each reservoir. Bottom line is, I'm not comfortable taking anymore material off than I have. I had hoped that a light touch with the grinder and I'd be golden. Not so with these particular wheels and calipers. As of now I'm in agreement with ntsqd, a poster on the 60 tech forum who advises against grinding calipers.

Speaking as a former brake design engineer, that is a bad idea.
Speaking as someone who has had to replace a caliper while on the road, that is a bad idea.

https://forum.ih8mud.com/60-series-wagons/466733-where-can-i-get-longer-wheel-studs.html#post6451310 < from the 60 tech forum

 

[camcruiser13]

They should be fine. Weights will be fine. They can use self adhesive oneson the inside. If they don't hit then don't grind more

 

[PixelWrangler]

I just ground mine down. I run 2.5 bs wheels same brand and everything as yours. Plenty of brake caliper to grind. Been running like that for several years no prob. I grounded mine down so I could take my spacers off.

Cam, thanks for chiming in, I believe I've read through all of your build threads, some of them 2 or 3 times. They've been great inspiration. I just finished skimming through your rear brake conversion to refresh my memory. I'm wondering if the Monte Carlo calipers are slightly smaller than the Eldorado ones? I went for the Eldorado calipers for the e-brake option, as my driveline e-brake was non-existant - drum only - and they solved that issue. Your Monte Carlos allowed the wheels to be mounted without grinding them? Damn. I was also wondering, it seems like I read you had the stock discs on the front of your '76. How do they compare in size to the 60 calipers? I'm just trying to figure out how much meat I actually have on mine. "Plenty of brake caliper to grind" is relative, and without seeing a cross-section of it I have no idea of how far I can go. The Eldorado calipers are pretty straight forward where I had to remove the material, I could see what I was doing, and knew as long as I left enough for strength, I would be fine. These calipers are new territory for me and ignorance is not bliss. I can just see myself hitting it one more time for good measure and where'd that fluid come from?!? I guess I need to find a junk 60 series caliper and grind it until I do break through or section it. Then I could move forward.

They should be fine. Weights will be fine. They can use self adhesive oneson the inside. If they don't hit then don't grind more

Yeah, there is plenty of room for the wheel weights on these wheels, self adhesive or on the rim, both areas are clear. I suspect the self adhesive ones would be less likely to get knocked off while wheeling, true?

If they don't hit then don't grind more

So you are saying as long as the calipers don't hit the wheel, no matter how little clearance, I'd be good? That would be sweet!

 

[PixelWrangler]

Decision made!

I spent many evenings over the past week searching through more threads on the 60 series tech site. I found more references to grinding the calipers than I had previously and with my new “hands on experience with my own rig, I was able to understand more of what they were talking about. It was interesting to read that many had varying results using the same wheel as I purchased on their stock calipers. Some said they didn’t have to grind or use spacers at all, some said they had to grind one side and not the other, while others said they definitely needed the spacers. Seems like the consensus was that there was some variance in the caliper castings. Bummer!

Based on the many recommendations I’ve received and the numerous posts I’ve read, I’ve made my decision. I’ve ground a good 1/8” off the corner of the right side 60 series caliper. Not knowing for certain exactly how much meat there is left on there, I’m going with the 1/4 spacers I have for the front. I prefer to err on the side of caution when it comes to my brakes.

The Eldorado calipers in the back are another story. I’m satisfied that I can safely grind off enough to clear the wheel. This afternoon I took a bit more off of the right side that I had ground previously and moved on to the left one. It didn’t take nearly as long to grind that side down since I knew how much had to come off to clearance the wheel. When I got it to where I thought it needed to be, I bolted the wheel on and had a look. WTF! I had more than 1/8” clearance! I double checked with the template I had made from the other side. Right on the money. OK, so what would cause the difference? I thought about the adapter that held the caliper to the axle. Wondering how much wiggle room there was in that mounting. I loosened the bolts on the right side, the one I had ground down first. Gave it a good shove and it slid over a bit! WooHoo! Now I have more than 1/8” clearance on both sides in the rear without spacers and feel confident that the calipers are still plenty strong.

I was concerned because as I had previously noted, with the 1/4” wheel spacers, I only had about 3/8” of wheel stud showing, not enough for a lug nut. According to ntsqd from the 60 forum, you need at minimum 12mm of bite on a 12mm stud. I’ve got that and more on both the front and the back now.

Having found some movement in the back calipers, I started thinking about the front ones. Would there be any room to slide them a bit away from the hub? Is that where the variance is that people were finding when fitting the same wheel to the same caliper on different rigs? So I pulled the left front wheel and loosened the caliper.


Pause for dramatic effect…














No, the 60 series caliper has a pretty tight fit on the axle, very little room for movement. 1/4” wheel spacers it is. Done!

Moral of the story, before grinding your calipers, see if there is any room for adjustment. I didn’t need to grind as much as I did off of the Eldorado clippers. Do I regret doing so? Not in the least. I don’t know for certain that the wheel would have hit the caliper had they both been pushed in tight to the hub. I do know that it would have been very close if it did clear. I do know that I have good clearance now and don’t feel that I’ve compromised the calipers at all with the amount I’ve taken off.

One last thought regarding ntsqd’s comment that I quoted earlier about what do you do when you have to replace a ground caliper while on the road. I’ll be caring an extra set of 1/4” spacers with me should that ever happen. Much smaller than a battery operated grinder. Though the grinder might be a good addition to a trail kit.


Today was a good day!