Again, I searched. The problem seems to be that there isn't a lot of resolution in these types of "issue" threads. A lot seem to die out with numerous suggestions, but no definitave reply stating "this was it, its fixed."
This is another one of those things I'm trying to clear up BEFORE I go to get an alignment.
My RF pads are dragging signficantly more than any other corner. LF wheel will spins maybe 10 revolutions before coming to a stop. You can hear a bit of pad drag on the LF (normal, I know), but the RF wheel only rotats about 2 (the pedal drag is distinct and continuous).
Worse still, I have a TON of brake dust on the RF wheel from driving the car to work 4 times, and test drives...only. Maybe 300 miles total.
The car also veers right on initial braking, but it doesn't continue to veer. IE, On fist application of brake it jumps right, but once pressure stabilizes the car decelerates in a straight line even with hands "off the wheel".
I rebuilt and painted the calipers last month (admittedly, my first rebuild...so it could be the monkey with the wrench). I've removed the clips and springs. I've adjusted the brake pedal pushrod length to the point that the brake lights stayed on (er...can you say dead battery ). Pins are lubed with CV2, also checked for free movement.
At this point, I'm thinking either:
bad caliper / bad rebuild
bad proportioning valve
bad master cylinder
The MC seems the least likely because its only one wheel, not front/rear.
I'm running PF97s on all 4 corners, and brand new Castrol LMA. All brake parts are 1992 original (AFAIK). There was no rust in any caliper cylinders, and everything went back together without any perceived issues.
Region: Ohio Valley Region
Car #: 35
Year : 1999 Posts: 170
I run clips and springs on my calipers, did you "remove" them permanently? Of the things on your list most likely I would think its the caliper. the Master would have the same effect on all the brakes. I don't know much about the proportioning valve but would expect it falls in the same class and the Master. One think not on your list is the Hub, I would check it without the caliper on. If you did not have the problem before your rebuild then that is the likely cause.
Hubs rebuilt 3 weeks ago. They don't spin like JD's in his video, but they both spin similar to each other. And the pads are definately dragging much heavier on the RF. Its audible when you turn the wheel by hand.
The proportioning valve is in series with the RF brake line coming from the MC. The LF brake line comes straight off the MC and does NOT pass through the prop-valve. Hence my suspicion. And the reason I think the MC is NOT at fault.
Brake lines are brand new braided.
New caliper, sure...no harm done in a new caliper. I was hoping to avoid the buying stuff from Mazda one at a time thing. So much cycle-time involved in that. Buy it, try it, buy the next thing, try it...etc. Weeks go by.
I suppose I could buy a prop-valve and MC along with a new caliper.
Now that I think of it, the RF was a little difficult to bleed. At the time I chalked it up to perhaps being completely full of air. I had to resort to the "open, push, close, release, open, push, close, release" method to get it to bleed. Even after fluid started coming out it was still VERY slow to bleed.
I don't know if the unmodified car exhibited the same issue. I never checked for brake drag before dissasembly. It drove fine, but so does this. I don't know if I would have made note of a turn on initial bite...or just attributed it to one of many quirks in a 214,000 mile donor car that the seller got in the breakup. I'm pretty sure this was a revenge sale.
Car #: 68
Year : 91 Posts: 2359
So take it all apart, and switch disk/pads from side to side and report back.
Sounds to me like you have something bent or caliper sucks. While apart inspect and compare caliper brackets. (forget that, I just re-read your bleeding issue, just replace the caliper)
This may be a good time to start buying spare parts (used is okay especially for these types of issues), you'll need them in the future. Also a great time to start finding fellow racers with spare parts. You'll find we do a lot of horse trading/sharing.
Here I'll ask, anyone in the SW got a spare NA used RF caliper Tom can try on his car?
-------------------- Bruce Wilson 2010 Oregon Region Champ 2010 Monte Shelton Driver of the Year 2010 25 Hours of Thunderhill E3 and Under 2 liter Overall Champion Oregon Region SM Class Advisor
Thanks for the advice. As I've noted in another thread I haven't met anyone in this class yet. I've been to a couple scca meetings kinda hoping to, but it was all srf guys.
I guess I hadn't felt presumptuous enough to ask to borrow parts. Im in the dfw area.
I'd noticed from following along, over the last year, that people trend to replace, and then rebuild the old part and put in the spares bin. So that is what I have been doing with other parts I've removed.
My tendancy has been to buy new...particularly for critical parts. At 214 k, it is a higher mileage donor..most parts appear original. Only the lf hub has clearly been replaced (new style).
Car #: 23
Year : 1995 Posts: 912
You never answered Frank Todaro's question about whether you permanently removed the clips and springs. The springs pull the pads away from the rotor in a uniform manner, so without the springs its entirely possible that one side has the pads resting against the rotor and the other side not so much.
I agree its frustrating reading other threads where there is no resolution, just suggestions. Its also frustrating offering simple suggestions that the OP doesn't rule out.
-------------------- Rob Gibson RJ Racing 2010 NASA Nationals TTE Champion 2008/2009 WERC Champion 2007 NASA SoCal SM Champion rjracing.net Weekend-Racer.com
Sorry, I missed that question in all the others. I was running the springs and clips until last weekend. I didn't intentionally neglect to answer it. I have ben trying to respond to all...I just missed it.
I removed them while troubleshooting the squeal that turned out to be my speedo cable. Brake drag preceded removal of clips and forums...and did not change after removal.
Sorry...my statement was really meant to say that the OP often doesn't return to the thread to clear up the final outcome. So, you can read lots of suggestions from the kind folks who try to help...but, not what the final answer turned out to be.
In the few question threads that I've started...uv tried to make a point to come back and say what I finally found the issue to be (eg speedo cable).
I have a prop valve, and 2 calipers in my mazda cart as I type. I was going to get a MC, too...but, they are on back order.
Car #: 17
Year : 97 & 99 Posts: 107
Did you put the grease the piston and seal when rebuilding?
If you did, unfortunately it's time for a new or reman caliper. Some times when the caliper's get too worn, the piston rocks inside the caliper bore and they stick not releasing properly and thus causing brake drag. Only way to fix realistically is to replace it.
Region: NWR / Oregon
Car #: 88
Year : 95 Posts: 2000
The other thing that happens with 20yo calipers, is that they probably didn't have the freshest, thickest pads in them, so they spent a lot of time not going all the way back into the bores. The black nasty brake fluid causes corrosion on the deepest part of the bore that hasn't been touched in years, and you have a sticky spot.
If you're going to change the brake prop and MC, I'd do them both at once, and bench bleed the MC before installing it. Unless of course you want to spend most of the winter bleeding and rebleeding the brakes.
-------------------- Keith Novak (Will work for tires)