I have a ford explorer 8.8 rear end that I shortened myself. Despite measuring like crazy, one side is still a bit longer than the other ~2mm. Not sure if something happened during welding (a problem for another time)…The reason for my message is: I’m mocking everything up so I can measure for wheels & ride height, I am looking to buy the rear brakes. I see that the kit from wilwood that is designed for the explorer states that the offset is 2.54”.. the issue here is that given that offset and the slight wonky-ness of the rear end, I’m not exactly at the 2.54 offset. In fact, driver side is 1.18mm over and the p***enger side is short 1.02mm. How critical is this offset measurement? My understanding is that this is what centers the rotor to the calipers so it seems fairly critical… If I’m not dead nuts on what are my options? Shims on the short side and possibly machine the axle and/or housing flanges for the longer side? Should I s**** the rear end and try shortening again?
Probably an off topic forum ? but the Wilwood setups I’ve used have shims to center up caliper. I wouldn’t mess with anything until I had the brakes. Wilwood’s tech guys are usually good on answering this type of stuff.
You would think that the unmodified side would be right to spec with Wildwood's offset but it's not for whatever reason. I called them and asked them about this, the response was something along the lines of "ford axels were all over the place regarding backspacing - we settled on 2.54""... Regarding the two measurements per side, I don't have much play in the axels, I think the play comes from the thickness and/or wear of the c-clips. The play in my axels is in the very low thousands of an inch. That said, my measurement was in the "out" position. I did not measure the "in" but I highly doubt that will reduce +/- 1mm difference. The play is barely noticeable.
Sorry I may have posted this in the wrong area - I don't post here much. I don't see an option to move to the correct area.
A moderator can move the thread to the "off topic forum" if they see fit. The wilwood brakes I've installed come with 4 shims per bolt, that fit between the bracket and caliper. This gives about 5mm adjustment range. No, the calipers are fixed, and they have pistons on both sides. The caliper has to fit over the rotor with sufficient clearance on both sides. this is the wilwood diagram for the brakes I installed on the back of my 62 Corvette. I expect there is some difference compared to the 8.8 rear, but this is generally how they work. Part 11 are the shims, which are 3/8" washers.
That’s up to the boss But disc brake stuff usually gets moved by them anyway, the brake set ups from Wilwood uses shims. So you are probably ok. I would t change anything on the rear end until you got the brakes and something was off
I'm still stuck on the 1.18mm .....that's about 0.040" I'd like to think that could be absorbed somewhere in the ***embly.
yeah seems silly but this difference has my OCD in overdrive I’m also not sure how tight the tolerances need to be for these parts hence why I’m asking for feedback.
Stock 8.8" axles in 4x4 Fords are 2 7/8" difference side to side and they work great, so I sure wouldn't sweat 1mm difference. I left mine full width for my '39 Chev and driveline runs at an angle, but it has no affect on how well it works. I've installed 8.8" Ford disc brake axles in builds I did for others and the stock disc brakes worked extremely well without needing to upgrade to aftermarket. I personally prefer factory brakes so I'm not tied to a custom maker like Wilwood if I ever need any brake parts in the future.
I think he is referring to axle offset not pinion offset [this is where terminology can be confusing]
With regards to an 8.8 with c-clips, changing ring/pinion can require different carrier shims for proper backlash, which moves the diff center pin side to side, which in-turn moves the axles in/out of the housing depending on how the carrier is shimmed. Without pre-***embly before welding the ends on, unlikely both axles will end up with the same brake offset. If you want the same brake offset on both sides, change to 9" style ends/bearings/axles. Grant
A lot can be said for "Not reinventing the wheel" The "Big Ford" bolt pattern is the same as the Exploder bolt pattern [The flange registration diameter is 0.025" smaller] But he will need 9" axles of the correct length. [custom axles] You cannot press 9" axle bearings onto an 8.8" 31 spline axle. A motor machinist can grind them down slightly to the correct diameter to fit properly. After the grinding process the axles should be "heat treated" BUT this should be done anyway to stress relieve the shorter R/H axle when used in the L/H side. It is like ******* into a cash register........ It is going to run into money
Sorry, but the pistons still "float" inside the caliper as soon as the brake pads start to wear. Wilwood told the OP that the Ford 8.8 has different backspacing across the board and they have elected a specific measurement. Since their package includes shims, I would suspect the perceived problem has already been addressed. Install the Wilwood set up and follow the directions, I would expect everything to work out OK. On the odd shot that there is a problem, or the whole deal is too much and is it really is screwing with the OP's head, he can have the short side caliper mount shaved that 1 point whatever mm between the caliper center line and where it bolts to the axle housing. That should position the short side at the proper clearance, and then just shim the long side to the proper clearance.
Lots of good info here guys! Thank you so much! I think I’ll order the brakes then go from there, I’ll keep you posted.
Closing the loop on this - ordered the willwood brake kit, definitely does not line up perfectly. The p***enger side should be ok with some of the supplied shims. The driver side is another story - pretty tight and may require a bit of machining of the supplied caliper bracket. Definitely doable…
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