Eldo calipers without using the e-brake

[nvrstuk]

Yeah, I found one that isn't and had all kinds of issues pushing fluid to the rear.

 

[DirtDonk]

From what I've read almost all MCs are 50/50 with proportioning done outside the MC. But I've never found a definitive answer to that matter.

Probably because there likely isn't one. There are probably master cylinders out there that do bias, and those that don't.
For our purposes though, the general Ford units from back in our day, probably did not have any internal bias. At least not that I've come across in my limited experience with the subject.

Paul

 

[nvrstuk]

What brand adjustable bias valve do you have? It should be able to dial down that press so the rears don't lock.

There is more to it than brake bias tho.

Gotta ask about suspension and the rear unloading too. If the front is diving and the rear is unloading you could have very little weight on the rear axle during a full emergency stop.

Like Tim mentioned, on two different types of brake bias valves I could dial the pressure down so the rear wouldn't lock up unless I was on gravel.

I used to run a 1.33" dia MC and now Tim and I are both running a Chev 1.25", Micro lock, Chebby JD6 frt & rear, no rear premature bias

 

[gunnibronco]

What brand adjustable bias valve do you have? It should be able to dial down that press so the rears don't lock.

There is more to it than brake bias tho.

Gotta ask about suspension and the rear unloading too. If the front is diving and the rear is unloading you could have very little weight on the rear axle during a full emergency stop.

Like Tim mentioned, on two different types of brake bias valves I could dial the pressure down so the rear wouldn't lock up unless I was on gravel.

I used to run a 1.33" dia MC and now Tim and I are both running a Chev 1.25", Micro lock, Chebby JD6 frt & rear, no rear premature bias

I'm using the Wilwood prop valve set at maximum reduction. It says it's able to reduce the rears by 72%, the most on the market.

I know the rear is lifting under braking, causing the rears to lock up. I can lock the rears before the fronts on pavement. It is at low speed, with intentional heavy braking. I cannot get the fronts to lock up at all. I'm running 5.5" Deaver front springs (set to 3.5" lift) on radius arms (typical Ruffstuff/Barnes DIY kit) and 54" Chevy Tahoe leaf springs and a shackle flip. The Tahoe springs have the same spring rate as the EB springs. I know the rear leaf set up is unusual and could well be causing the difference in how my truck is acting. There are at least one or two others here on CB.com with the same rear bias problem with similar brake set ups (I'm sure their suspension is different than mine).

There is another discussion going on here regarding brakes and it was concluded the change from JD6 rears to Eldo calipers will change my bias from 56% front/44% rear to about 62.5% front/37.5% rear. I do have an aggressive pad on the rear caliper and I might have pulled the bias forward with a crappy organic pad on the back instead. I spoke with a few engineers, two from the automotive industry and they agreed the best way to fix it was with the Eldo caliper, not a pad swap. So here we are.

 

[nvrstuk]

Interesting on the pad vrs caliper.

72% reduction (bias valve) on the rear with a 56%/44% bias to start off with and it still doesn't stop rear lockup at slow speed w/o locking the front makes me think the front pads possibly were glazed when braking in. That's pretty common but with your research/skills I'm thinking that you already looked into that? If the front never locks due to the pads being glazed that could point 100% of the problem to the rear when it might not be the entire cause of the issue? Just a thought. I did a lot of brakes and did a couple brake schools but that was eons ago. EONS

Did the engineers suggest pad changes as a fine tune if the Eldo's/Wilwood can't do it all on their own?

I think you are on the right track with the reduction in bias using the Eldo calipers. There is a lot to a complete brake system design- I really enjoy the number crunching.

 

[gunnibronco]

Interesting on the pad vrs caliper.

72% reduction (bias valve) on the rear with a 56%/44% bias to start off with and it still doesn't stop rear lockup at slow speed w/o locking the front makes me think the front pads possibly were glazed when braking in. That's pretty common but with your research/skills I'm thinking that you already looked into that? If the front never locks due to the pads being glazed that could point 100% of the problem to the rear when it might not be the entire cause of the issue? Just a thought. I did a lot of brakes and did a couple brake schools but that was eons ago. EONS

Did the engineers suggest pad changes as a fine tune if the Eldo's/Wilwood can't do it all on their own?

I think you are on the right track with the reduction in bias using the Eldo calipers. There is a lot to a complete brake system design- I really enjoy the number crunching.

I didn't think of the front pads glazing. I'll have to take it apart and look. I don't *think* I did anything to glaze them. New pads, rotors and new (not rebuilt) calipers. If anything I might have glazed the rear pads, on the first drive I realized I had the line lock closed on the rears (less than 1/2 mile).

Yes they did mention a less aggressive pad could help the bias. Interestingly on the thread below one suggested an EE rated pad , but I just picked up a cheap set of organic pads for the Eldo calipers and they are FF rated, so I'm not sure I could even find an EE rated pad if I wanted to. My current JD6 pad is a GH rated, and I *think* my fronts are FF. I was originally planning to use the JD6 calipers up front but plans changed and I used the stock 96 F350 brakes in front and the JD6 in the back (its a long story started planning 5x5.5 and changed to 8x6.5). - See US Edge Code discussion in the link below regarding pad ratings- This was new info to me!

If you haven't seen the thread below there is a lot of good info and tech stuff on brake bias.

This is where my posts start about my bias issues, but the whole thread is very interesting if you like that kind of nerdy stuff.
https://classicbroncos.com/forums/threads/new-brake-kits.320833/page-6#post-3509259

I've also spoken with an engineer with an aerospace company and an engineer with a specialty suspension company who is here on CB.com and Colorado Classic Broncos, they all basically said the same things.

 

[nvrstuk]

1st off, thanks for the thread link! Somehow I missed this thread.

2nd, I used to be on the CC list but haven't spent time there for quite a while!

 

[kman67]

I replaced my El Dorado calipers with 89-97 chevy S10 4x4 front calipers. They fit in the brackets I originally got from BC broncos. I’m not sure of the piston or pad size, I wasn’t able to find that #. If you aren’t using the parking brake, that might be an option.
Kyle


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[gunnibronco]

I replaced my El Dorado calipers with 89-97 chevy S10 4x4 front calipers. They fit in the brackets I originally got from BC broncos. I’m not sure of the piston or pad size, I wasn’t able to find that #. If you aren’t using the parking brake, that might be an option.
Kyle


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There are 2 "Eldo" calipers.

The 76-78 Eldo are larger (7" pin spread, 2.5" caliper piston) and match/replace JD6 & JD7 front brake calipers. These work on the typical "1-ton disk brake swap kits" like Lugnut4x4, Ruffstuff, etc. This is what I'm going to use.

79+ Eldo calipers are smaller (5"ish pin spread, 2" caliper piston) and can swap with the "metric" calipers like the 80s S10, Monte Carlo, etc front calipers. They don't fit the 1-ton disk brake swap rotors due to the thicker "1-ton" rotor. So to make these calipers work I'd have to find a rotor that fits my 14 bolt hub and make a bracket to hang the caliper. At this point I haven't found a rotor that fits this caliper AND my hub, so it's not really an option unless someone can show me a rotor that works.

Thanks

 

[kman67]

I didn’t know there were 2 types.
Thanks


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[gunnibronco]

I didn’t know there were 2 types.
Thanks


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I didn't either until recently.

 

[rocknhorse76]

Yeah the Ford 9” disc conversions that most Bronco vendors sell use the smaller metric calipers. 79 Eldo calipers for the kits with e-brake and S-10 style for kits without it.

 

[gunnibronco]

@nvrstuk
Your comment on possibly glazing the front pads got me thinking. When I first assembled the axle and brakes, I noticed the front pads dragged more than expected. Hub spins freely until pads/calipers are installed.

I'm now worried there is something hanging up my front brakes. Is this causing my brake bias problem? I'm not sure, but I need to figure out if my front brakes are right or not.

For context: 1996 F350 D60 knuckles & brakes- all new (not rebuilt)brake parts: Raybestos calipers, rotors, pads, master cylinder with about 500 miles all new brake hoses (Crown Performance).

I pulled the front brakes apart and looked for pad glazing. I had trouble finding too many pictures to compare. My pads did feel very smooth and had a sheen. I'm not sure how well that will show up in this picture. Most the pictures I've found on the internet show pads in far worse condition so I'm not sure how bad this is or if it would be considered glazed.

https://photos.app.goo.gl/5pFFRvG4dpMv2RaM6

I did some Googling/Youtubing and decided to give the pads a quick sand (I know, I know) to remove the top layer of shiny material. I also resurfaced the rotors with a Scotchbrite/Roloc disk on a die grinder. I did the same to the rear pads and rotors. Fronts drag again after installation. There is plenty of clearance for the pads to rotor with the caliper pistons pushed back. After pumping the brakes back up and resetting the calipers the drag on the rotor returns.

Took the truck out again and specifically bed the brakes by doing hard braking from about 50 mph to 10 mph. By about the 5th time, the rears started locking up, the fronts are not. When I got home (long after the bedding process) I took a quick temp measurement on the rotors- ambient temp is about 45*, fronts read about 170*, rears 80*. Still lots of drag on the front wheels after the re-bedding process. Front tires won't spin 1 full rotation when spun by hand, rears will spin a little more free.

Edit- Maybe this amount of drag is ok. I'm just not sure.

Then I the did the following:

loosened the master cylinder from the booster to ensure no preload on the master- drag remained
loosened front brake line at master cylinder enough to drip- drag remained
loosened front brake line @ T fitting on axle- drag remained
opened bleeder on caliper- drag remained

If something is wrong, it would mean both calipers are bad. Both are new, both are acting exactly the same. Any advise? Suggestions? Something I'm overlooking? Or is this just normal and I'm overthinking it?

 

[ksagis]

How hot are front rotors / wheels with normal driving? If they’re 170, that seems way too hot, likely driven by your draggy brakes.

Are these floating calipers?

 

[nvrstuk]

When you pry the caliper back like you're removing the caliper off the rotor, how quickly does the cup try to extend and push the pad back against where the rotor was? Does it move on it's own and create the same amount of drag (when put back over the rotor as before or does the cup sit there till you hit the brake pedal then the drag on the rotor is created again?

Discs always drag, but not so much to create extremely hot rotors. I learned that back in HS as I burnt my finger when I was checking the brg caps and thought the rotor looked/smelled hot. Ouch! lol These were the rotors on my girlfriends (wife now), MGB. I had no idea they had that much drag. Long term memory = I experienced/lived the event ha

 

[gunnibronco]

How hot are front rotors / wheels with normal driving? If they’re 170, that seems way too hot, likely driven by your draggy brakes.

Are these floating calipers?

170 was after arriving home after normal driving for 10+ minutes after heavy braking/bedding. Some highway miles and a few mellow intown stop signs and pulling into my shop.

Yes they are floating calipers, both new, greased, etc.

When you pry the caliper back like you're removing the caliper off the rotor, how quickly does the cup try to extend and push the pad back against where the rotor was? Does it move on it's own and create the same amount of drag (when put back over the rotor as before or does the cup sit there till you hit the brake pedal then the drag on the rotor is created again?

Discs always drag, but not so much to create extremely hot rotors. I learned that back in HS as I burnt my finger when I was checking the brg caps and thought the rotor looked/smelled hot. Ouch! lol These were the rotors on my girlfriends (wife now), MGB. I had no idea they had that much drag. Long term memory = I experienced/lived the event ha

I don't remember the pistons extending after pushing them back. I had no problem reinstalling the the caliper. I didn't check drag before pumping the pedal. The pedal was very soft for the first pump then much firmer. I expect the caliper was retracted and needed extended back to meet the rotor.

The hub and wheel is not hot. The rotor is hot to the touch. I'm just not sure if the drag I'm seeing is "normal" or "excessive". I get about 3/4 of a rotation when spinning a front tire by hand (same on both sides).

 

[gunnibronco]

The front pads were hanging up and not retracting. I followed advice I got on a FB post to check the sliding surfaces on the brake pad backing plates. It wasn't obvious but when I took a file to the ends of the backing plates it showed that they weren't cut cleanly. I filed off just a bit until the "burrs" were removed. The added clearance made a huge difference. The hubs spin much freely than before. The truck rolls easier as well. After a similar drive the rotors only read 110*. I'm expecting my mileage will improve as well. I had noticed a significant drop in fuel mileage since my axle swap.

The rear bias still remains so I'll be swapping in the Eldo calipers sometime soon. I'll be putting some miles on the truck before them just to make sure of how it's performing.

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[ksagis]

The front pads were hanging up and not retracting. I followed advice I got on a FB post to check the sliding surfaces on the brake pad backing plates. It wasn't obvious but when I took a file to the ends of the backing plates it showed that they weren't cut cleanly. I filed off just a bit until the "burrs" were removed. The added clearance made a huge difference. The hubs spin much freely than before. The truck rolls easier as well. After a similar drive the rotors only read 110*. I'm expecting my mileage will improve as well. I had noticed a significant drop in fuel mileage since my axle swap.

The rear bias still remains so I'll be swapping in the Eldo calipers sometime soon. I'll be putting some miles on the truck before them just to make sure of how it's performing.

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Interesting, you mean the issue was the flat part of the backing plate or the “ears” or “tangs”. Hard to imagine the flat part that the piston pushes on would be an issue.

 

[gunnibronco]

Interesting, you mean the issue was the flat part of the backing plate or the “ears” or “tangs”. Hard to imagine the flat part that the piston pushes on would be an issue.

Yes, these are 1996 F350 brakes (very similar to the next gen Super Duty brakes). The ends of the brake pads ride on a stainless shim on the caliper hanger. I took just a bit off the ends of the pads where they ride on the shim/caliper hanger.

https://photos.app.goo.gl/pXy8z27sQjUKZRRS8

I never would have expected this was the problem, I disassembled and reassembled everything multiple times trying to figure out what was going on. Before filing, everything fit together fine and the pads slid on the hangers by hand, nothing seemed wrong. But obviously when the brakes were applied they would bind up and not fully release. The bind only occurred when the brakes were applied with the h-booster running. Even after pumping the brakes with the motor/h-booster off, the hubs would spin fine. Thankfully someone on FB mentioned this as a possible problem. I really didn't think that was going to help, but it made a huge difference. I don't know if they would have self clearanced over time and gotten better.