Wilwood Pedal Box - Clevis Clearance

[John Ibele]

I didn't see this specific question addressed in a quick search of the forum, so I figured I'd do a quick check with the experts ...

I'm doing a final check of items under the DS footbox before I close it up, so went through the Wilwood pedal box setup and instructions one more time. In checking total clearance between clevises and brake pedal, I was surprised to find that my total clearance is closer to 0.10" or a little over - not the 0.20 - 0.25" clearly called for in the Wilwood instructions.

Usually I have a reason for doing things (:rolleyes:) ... so did some more measurements, and concluded that I had set up the center-to-center distance between clevises to match the center-to-center distance between MC's, which is 1 5/8" on my setup. This would seem to be what is needed in order to keep the pushrods from binding (exiting straight out from the MC's)... dialing in to 0.2-0.25" is not only a bit of PIA at this point, but also a setup that will have the pushrods splayed apart, not parallel. So I can't dial in to the total clearance Wilwood asks for without creating a condition they make clear I should avoid.

There is no binding and there's plenty of free side-to-side movement of the clevises at all points of brake travel, which I think is the most important thing. So I'm leaving like that until I talk with Wilwood on Monday unless someone can give me a convincing reason to change things. Comments / clarification of my confusion appreciated.

[Blitzboy54]

Can you post some pictures? Seems weird that your MC distances would be different. I have the recommended clearance and everything looks pretty straight

.010 sounds tight but maybe not.

[edwardb]

Not sure why you think Wilwood would tell you anything different than what they have in their instructions. Just to be confirm though, the .20 - .25 dimension is both sides together. So it would be around .10 on each side. Maybe that's what you have? If so, it's OK. However, if you're only .10 total between the two sides, you need to adjust it to be how they describe. You're talking less than 1/8" and the change that makes to being parallel isn't enough to matter. Certainly nothing like the exaggerated diagram them show in their instructions. I've done a number of these (so have hundreds of others) and they set up and work just fine as instructed. Now is the time to get it right. You don't want it binding plus to adjust once the car is done and everything buried will be much more difficult.

[John Ibele]

Not sure why you think Wilwood would tell you anything different than what they have in their instructions. Just to be confirm though, the .20 - .25 dimension is both sides together. So it would be around .10 on each side. Maybe that's what you have? If so, it's OK. However, if you're only .10 total between the two sides, you need to adjust it to be how they describe. You're talking less than 1/8" and the change that makes to being parallel isn't enough to matter. Certainly nothing like the exaggerated diagram them show in their instructions. I've done a number of these (so have hundreds of others) and they set up and work just fine as instructed. Now is the time to get it right. You don't want it binding plus to adjust once the car is done and everything buried will be much more difficult.

Yep, agree Paul. And in staring at it some more I came up with what I believe is the reason it's set up the way it is. While setting it up as called for seems to have the pushrods slightly farther apart at the clevises than at the MC's, any movement of the balance bar away from perpendicular is going to bring them first closer to parallel, then parallel, then closer together at the clevises than at the MC exit. The pushrods are designed to handle this lateral movement, and this is the setup that gives you the greatest movement of the balance bar without any binding. Could be wrong, but it's how I'm making sense of what's asked for.

To confirm, I have 0.10" total, not each side, so I have some adjusting to do. In looking at the instructions it appears I was able to first mount the MC, and then turn the pushrod to thread it into the clevis. If so that's really good news, because it means I'm not facing a removal of the MC's, merely unscrewing the pushrods, unfastening the brake pedal to be able to spin the clevises, and adjusting them to get the proper clearance. Glad I checked.

I tried briefly to unscrew the pushrods by hand, but there's some pretty serious resistance at the pushrod entrance into the MC. Will get back at it tomorrow to see if I can rotate them back out without buggering threads.

[Blitzboy54]

I think you can unscrew the balance bar out of one clevis then spin a few turns and back in, giving you the wider gap. I wouldn’t even mess with the push rods

[John Ibele]

I think you can unscrew the balance bar out of one clevis then spin a few turns and back in, giving you the wide gap. I wouldn’t even mess with the push rods

Thanks Jesse. Tried that yesterday but seemed to stop or bind after a time. It seems like it should be possible to keep backing it out though; I’ll look at that again today first.

[John Ibele]

I figure if it was worth a post, it's worth a follow-up post showing resolution to the problem.

I called Wilwood tech support and got some helpful and knowledgeable advice. I had some questions to satisfy my curiosity about the design and setup recommendations, but I'm going to leave those out of this post so the main message doesn't get lost. That message is: follow any instructions related to safety items to the letter. In my case, it was clear that the setup was not going to bind in any situation ... but what if someone else buys the car someday, changes something about the brake setup, and moves the balance bar? It needs to be set up properly. Period.

Two possibilities for how I got here in the first place: I set it up - temporarily - assuming I could make this adjustment later. Don't do that. It will never be as easy to adjust as it is when out of the car. Second, I may have actually had the required clearance (barely) in the first place. I'd recommend coming up with a spacer of 0.20" (stack of washers, quarters, whatever) if you want to double-check the spacing in your assembled pedal box. It's hard to make an accurate measurement in an installed footbox any other way. I didn't think of that prior to disassembly, unfortunately. Leaving things for "later" can be a challenge with a Forever build like mine, and no amount of build log writing or notes on the car seems to catch everything. But I'm happy that I double-checked before buttoning up the DS footbox aluminum.

Yes, you can dial in the proper clevis spacing with the pedal box in the car if you need to, and you can do so without dismounting the master cylinders from the pedal box, or worse (ugh), undoing your brake lines.

Required steps:

"Do your stretching exercises and meditation first." Wilwood tech recommendation. Funny guy, but actually, he's not joking.
Back off the jam nuts on the pushrods and keep on spinning them until they reach the end of the threads. You can then use them to spin the pushrods to back them out of the clevises. The seals will want to grab the pushrods, so you'll want to hold onto those while you spin the jam nuts.
The clevises are now free from the pushrods, but there's not sufficient clearance to rotate them.
Remove the C clip from the brake pedal pivot, and slide the brake pivot out to free the brake pedal. To do this, you'll need to remove one nut / bolt pair that fastens the Wilwood cast aluminum to the FFR mounting bracket (the bolt is backed out in the first photo). DON'T BACK the SHOULDER BEARING OUT ALL THE WAY - it will save you much grief if you can leave it in far enough to hold the spacer that goes between the brake pedal and the pedal box on the PS side of the brake.
You can now pull the brake pedal up enough within the pedal box to spin the clevises to obtain the required clearance.
Now, THE MOMENT YOU'VE ALL BEEN WAITING FOR, you get to somehow hold the brake in the desired position, while getting the required spacers back in place, and pushing the shoulder bearing back in. And finally, the C-clip back on. Is that three things with two hands? Yes it is. Fresh grease is good for the joint, but also for keeping the spacers wherever you push them.
Spin the pushrods back in, and tighten the jam nuts. You can't rely on being able to use the jam nuts to spin the pushrods this time, though, and it was not possible for me to spin them by hand. Protect the pushrod threads with a strip of rubber or tape and use a pliers to spin them in.


I had both top panels and the outside panel of the DS footbox off when I did this. Step six took multiple steps away from the car. I won't say impossible, but if any additional panels were in place, completion would have involved multiple bass-playing sessions with 'Immigrant Song' or 'Black Dog' at high volume. But now we're into individualized meditation techniques. That's just me.

Photos to adequately clarify the challenge ... any builder of a completed car knows it's crowded in there ...

https://live.staticflickr.com/65535/52734525899_1e172b6c03_b.jpg (https://flic.kr/p/2okYeiM)
Untitled (https://flic.kr/p/2okYeiM) by John Ibele (https://www.flickr.com/photos/familycobra/), on Flickr

Back assembled and all is right with the world ...

https://live.staticflickr.com/65535/52734686330_acf0993fd0_b.jpg (https://flic.kr/p/2okZ3ZQ)
Untitled (https://flic.kr/p/2okZ3ZQ) by John Ibele (https://www.flickr.com/photos/familycobra/), on Flickr

[JohnK]

Wow, my back hurts just reading that! :p Congratulations on getting it all sorted out. Thanks so much for posting all that.

[John Ibele]

Wow, my back hurts just reading that! :p Congratulations on getting it all sorted out. Thanks so much for posting all that.

... and in fact, that appears to be what's a bit stiffer than usual today ...

[Tooth]

This is interesting as this is a job I was also "going to do at some point". Only because I still can't decide if I want to use the brake bias adjuster I got from Breeze. Guess I need to get that sorted.

Thanks for posting this.