RoadRacer
01-02-2022, 02:06 PM
All of this is (my) user error, but there are lessons to be learned! I always like sharing my cockups because we all make them :D
TDLR; check and tighten all the locknuts on the balance bar assembly!
I get in my car this morning to drive to a cars-n-coffee, and there are very poor brakes at end of my driveway. I drive my car hard and fast every day, so this is unusual, but it feels like only the rears are working (which are of course the worst brakes on the car). Anyway, it's 7am sunday I drive carefully to the meetup and carefully back.
Back home, I remove the inspection panel above the pedal box and look in (this is the after photo unfortunately):
159592
First, the bias looks way off. the threaded balance bar (running vertical in this photo) is sticking out the rear mc side (top in photo) as far as it can go. Hardly anything on the front mc side. At (A) The nylon washer looks weird and it's all puckered up. Huh? When I look closer, the internal spherical bearing and nut is jammed HARD up against the nylon and rear mc bar.
Here's a better view of the internals. (If you didn't know, adjusting the balance bar by turning the threaded bar moves that bearing left and right inside the pedal, so the pedal pushes a little more on one side than the other)
159593
In my case that arrow'ed nut was jammed up against that black piece so hard that the whole thing is locked up. Only the rear master cylinder is getting any juice. I'd effectively given it maximum rear bias, and then stopped the balance bar even pivoting anymore.
It wasn't like this the last time I adjusted the brakes, but I noticed that locknut (B) was loose. So I can only assume that the constant vibration and brake pedal movements rotated my balance bar over time? It's been 5-6,000 miles since I adjusted this.
So, tighten locknut (B) after you set the brake bias! (duh)
Yes, dumb I know. But bear with me, it gets worse.
I then set the balance bar up so it's got some front bias - might be hard to tell from the first pic, but there's more thread exposed on the front mc (bottom of photo) now. The bearing is probably 2/3 to the front inside the pedal.
Then I noticed that the rear master cylinder rod (C) was longer than the front (D) - again, wrong! The front rod should be longer at rest, and then the bias pushes it back faster so it catches up and passes the rear. Hard to explain so here's the manual (https://www.wilwood.com/PDF/DataSheets/ds252.pdf). Again, it's the locknut. I wouldn't have believed it but the rod wound itself out over time (or I suppose I was smoking something that day?). So I had to adjust it back in and tighten up the locknuts C&D again.
The funny thing was that I hadn't noticed the brakes getting worse over time but as I go faster in the car I haven't been terribly impressed with brakes recently and have been talking to people about bigger brakes. Now it seems like I have brand new brakes! With a newly adjusted (AND TIGHTENED) balance bar it feels amazing again.
(BTW, it's not obvious from the photo, but I do have the required 0.2" total gap between the washers)
TDLR; check and tighten all the locknuts on the balance bar assembly!
I get in my car this morning to drive to a cars-n-coffee, and there are very poor brakes at end of my driveway. I drive my car hard and fast every day, so this is unusual, but it feels like only the rears are working (which are of course the worst brakes on the car). Anyway, it's 7am sunday I drive carefully to the meetup and carefully back.
Back home, I remove the inspection panel above the pedal box and look in (this is the after photo unfortunately):
159592
First, the bias looks way off. the threaded balance bar (running vertical in this photo) is sticking out the rear mc side (top in photo) as far as it can go. Hardly anything on the front mc side. At (A) The nylon washer looks weird and it's all puckered up. Huh? When I look closer, the internal spherical bearing and nut is jammed HARD up against the nylon and rear mc bar.
Here's a better view of the internals. (If you didn't know, adjusting the balance bar by turning the threaded bar moves that bearing left and right inside the pedal, so the pedal pushes a little more on one side than the other)
159593
In my case that arrow'ed nut was jammed up against that black piece so hard that the whole thing is locked up. Only the rear master cylinder is getting any juice. I'd effectively given it maximum rear bias, and then stopped the balance bar even pivoting anymore.
It wasn't like this the last time I adjusted the brakes, but I noticed that locknut (B) was loose. So I can only assume that the constant vibration and brake pedal movements rotated my balance bar over time? It's been 5-6,000 miles since I adjusted this.
So, tighten locknut (B) after you set the brake bias! (duh)
Yes, dumb I know. But bear with me, it gets worse.
I then set the balance bar up so it's got some front bias - might be hard to tell from the first pic, but there's more thread exposed on the front mc (bottom of photo) now. The bearing is probably 2/3 to the front inside the pedal.
Then I noticed that the rear master cylinder rod (C) was longer than the front (D) - again, wrong! The front rod should be longer at rest, and then the bias pushes it back faster so it catches up and passes the rear. Hard to explain so here's the manual (https://www.wilwood.com/PDF/DataSheets/ds252.pdf). Again, it's the locknut. I wouldn't have believed it but the rod wound itself out over time (or I suppose I was smoking something that day?). So I had to adjust it back in and tighten up the locknuts C&D again.
The funny thing was that I hadn't noticed the brakes getting worse over time but as I go faster in the car I haven't been terribly impressed with brakes recently and have been talking to people about bigger brakes. Now it seems like I have brand new brakes! With a newly adjusted (AND TIGHTENED) balance bar it feels amazing again.
(BTW, it's not obvious from the photo, but I do have the required 0.2" total gap between the washers)