D1: front brake calipers in the rear

p m

p m

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I have 110 calipers in front and am reasonably happy with the results.
One of the rear calipers is dragging - not seized yet, but inching there. I still have my perfectly good old front calipers sitting in my garage, and wonder if I can use them in the rear.

Clearly, I'd have to use front rotors in the rear as well; I will likely need a larger master cylinder, too. What I don't know if I can mount the front calipers without any major hacking. I will test-fit them this coming weekend, but I'd love not to have to remove/reinstall the hub more than once.

Whether you've done it or not, your comments are welcome.
 
MM3846

MM3846

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Does the caliper bolt on? I mean, rear brakes aren't doing much of the work. How much bigger are the rotors and pads surface area? If you do get it done, I'd wait on the master upgrade. Get it all working first, see how the pedal feels. Have any idea what master you could upgrade to? The hubs front/back are the same, so as long as the caliper bolts up you won't have any issue with rotor contact.

Personally just after doing the upgrade to vented D90 brakes up front with the bigger calipers I'm more than satisfied with braking performance... even with 75% functioning rear brakes. I'm running close-to-stock tires though. If you need more brakes, I think I'd start with better pads.
 
p m

p m

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MM3846 said:
I mean, rear brakes aren't doing much of the work.
Click to expand...
When your Disco loaded to the gills for a several thousand miles-long trip - all of it in the back - the rear brakes are doing 2/3 of the work.
When you're climbing a 30-degree slope and need to back up, rear brakes are doing ALL the work.
And when rears are stock, and fronts use 110 calipers, the fronts lock up immediately. It happens when I back down my ~6-degree driveway!

Upgrading the front to D90 or 110 calipers and pads and not doing anything to the rear was a mistake in retrospect.

Edit: besides that, all reman rear calipers have the side walls worn out, and the pads are free to fall all the way into the hub. At least the front ones use pins to keep the pads in place, radius-wise.
 
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ERover82

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No idea, but interested to see where this leads. I'd assemble without torque to see if things line up. Then either torque or abort.
 
lunchbox

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I tried it many years ago. The bolts don't line up perfect and the spacing is a tad off. I redrillled one of the holes on each caliper and put a washer in the space them out so the rotor was centered. I couldn't get the pedal to feel right. I think the booster may not be big enough for the extra piston back there. I already had D90 brakes up front and have removed all ABS components. The lines and master are all new as well. It just didn't work well. It always felt like it needed a good bleed.
 
p m

p m

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Thanks for suggestions, guys. I don't think I'll be doing anything that requires non-NAS, late-110 rear axle hardware - lead times for spare parts go up beyond my attention span.

lunchbox - my brake pedal feels that way already, despite my efforts to bleed all lines. I chalked it off to increased volume of the 110 calipers; the brakes aren't bad - definitely better than my other 96 D1's, despite bigger tires.

I may have to put off that conversion until after the trip to Colorado - too bad, have all D1 brake hardware at hand and have to replace one rear hub anyway.
 
MM3846

MM3846

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p m said:
When your Disco loaded to the gills for a several thousand miles-long trip - all of it in the back - the rear brakes are doing 2/3 of the work.
When you're climbing a 30-degree slope and need to back up, rear brakes are doing ALL the work.
And when rears are stock, and fronts use 110 calipers, the fronts lock up immediately. It happens when I back down my ~6-degree driveway!

Upgrading the front to D90 or 110 calipers and pads and not doing anything to the rear was a mistake in retrospect.

Edit: besides that, all reman rear calipers have the side walls worn out, and the pads are free to fall all the way into the hub. At least the front ones use pins to keep the pads in place, radius-wise.
Click to expand...

Ok, ok. Agreed. I barely have a week on the D90 front setup, but I'm liking it a lot so far. And I wouldn't know about the lock up issue, my ABS works mint :D I do have "new" Lockheed brand rear calipers but I did notice that the pad holding design is just inherently shitty.

ptschram said:
There was a UK company making brackets to allow for mounting of front calipers to the rear.

Have you considered 110 calipers? The mounting points are the same, pistons are larger and more friction area. Will need different rotors and might need different stub axles.
Click to expand...

So, non-NAS 110s rear calipers/rotors/pads will 100% bolt up to the rear? I'm confused about the part about stub axles if you're talking about the rear...

p m said:
The booster will not. A master cylinder might - but only from the disc/disc version (non-NAS).
Click to expand...

The stock booster is plenty, since these trucks were already disc/disc from the factory. You'll definitely need more master if you upgrade both the front and rear calipers... if there is a bigger master that bolts up, that would be awesome.
 
p m

p m

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MM3846 said:
The stock booster is plenty, since these trucks were already disc/disc from the factory. You'll definitely need more master if you upgrade both the front and rear calipers... if there is a bigger master that bolts up, that would be awesome.
Click to expand...
Here we're talking about either non-NAS, disc/disc, master or something else altogether. Corvette MCs are cheap and can be found anywhere, but I doubt they would just bolt up to a booster. Swapping the booster/MC combo only gets you deeper into hacking the truck.
 
MM3846

MM3846

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p m said:
Here we're talking about either non-NAS, disc/disc, master or something else altogether. Corvette MCs are cheap and can be found anywhere, but I doubt they would just bolt up to a booster. Swapping the booster/MC combo only gets you deeper into hacking the truck.
Click to expand...

Right, if it doesn't bolt up to the master I'm not sure I'd consider it. What about the NAS D90 master? Same bore? Do we know what the stock disco MC bore? What about a D2 master?
 
Tugela

Tugela

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There's been no mention yet of the proportioning valve. It's calibrated for the stock D1 brake configuration. I don't even know if that can be adjusted. Once you start putting different calipers on that alters the balance of power relative to how the proportioning valve is set.
 
MM3846

MM3846

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If someone is doing this and has already gotten rid of the ABS system, its best to just plumb in an aftermarket adjustable prop valve.
 
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