Turbo II rear brakes and MOMO horn buttons
04-19-06, 10:43 AM
#1
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Turbo II rear brakes and MOMO horn buttons
I didn't want to break this down into two separate posts, since the MOMO thing could've been moved.
Since I managed to work on both, I might as well put both of them into one thread.
My rear brakes (specifically the driver's rear) started to makes a ghastly "groaning" noise.
Checking the rotor, I see a "white" scrape mark all around the outer 1" edge of the rotor.
The grooving wasn't that heavy, so I thought some dirt or piece of rock got caught under the pad?
What made it odd is that the first few weeks, the groaning sound would come and go - it wasn't consistent.
Welp, I finally managed to take everything off, and I was horrified to find the brake pad had worn down to the damn metal backing plate.
I know the front brake pads have "squeal shims" that are supposed to worn you the brake pads are getting low, but my rears don't look like they have anything like them.
So if you're poking around back there, inspect the brake pads as much as you can!
The funny thing is that when I pulled all 4 brake pads (left and right), the one pad that was marking my driver's rear rotor (outer) was the only one worn down to the backing plate!
The other 3 pads had an easy 2mm to 3mm of brake pad left!
WTF?
I checked that particular brake caliper, and there was nothing weird - floating parts all slid fine, and the brake piston restracted smoothly into the bore.
At the same time (since I had to wait for the brake pads to come in at the local auto parts store), I was messing around with my horn.
I run air horns, and my first air compressor seized.
I had ordered a replacement air compressor, and I was ready to install.
When I had finished the install, it didn't work at all.
I managed to trace the problem to the horn button itself.
Funny that the MOMO horn button wasn't quote making good contact!
The DMM showed resistance floating anywhere from 900-ohms to 100-ohms, and sometimes would trigger the BEEP on the continuity test.
WTF?
I took the MOMO horn button apart, and it looks like all brass parts in there.
The center contact point on the bottom looked pretty dull, so I just sanded to a nice shiny surface - this fixed the intermittent contact problem.
So it looks like these MOMO horn button assemblies are not that reliable.
For the record, I run a MOMO Race 350mm, and it has been installed in the car for about 7 years now.
It has been through Sacramento, CA summers / winters...Las Vegas, NV summers / winters...and Hawaii humidity.
If you're running a MOMO horn button and getting problems with the horn, you might want to check the button itself!
Through all this troubleshooting, I rewired the horn circuit to a dedicated Bosch relay and bypassed all the stock crap - the wiring runs through the blasted "CPU".
Hope this helps!
-Ted
Since I managed to work on both, I might as well put both of them into one thread.
My rear brakes (specifically the driver's rear) started to makes a ghastly "groaning" noise.
Checking the rotor, I see a "white" scrape mark all around the outer 1" edge of the rotor.
The grooving wasn't that heavy, so I thought some dirt or piece of rock got caught under the pad?
What made it odd is that the first few weeks, the groaning sound would come and go - it wasn't consistent.
Welp, I finally managed to take everything off, and I was horrified to find the brake pad had worn down to the damn metal backing plate.
I know the front brake pads have "squeal shims" that are supposed to worn you the brake pads are getting low, but my rears don't look like they have anything like them.
So if you're poking around back there, inspect the brake pads as much as you can!
The funny thing is that when I pulled all 4 brake pads (left and right), the one pad that was marking my driver's rear rotor (outer) was the only one worn down to the backing plate!
The other 3 pads had an easy 2mm to 3mm of brake pad left!
WTF?
I checked that particular brake caliper, and there was nothing weird - floating parts all slid fine, and the brake piston restracted smoothly into the bore.
At the same time (since I had to wait for the brake pads to come in at the local auto parts store), I was messing around with my horn.
I run air horns, and my first air compressor seized.
I had ordered a replacement air compressor, and I was ready to install.
When I had finished the install, it didn't work at all.
I managed to trace the problem to the horn button itself.
Funny that the MOMO horn button wasn't quote making good contact!
The DMM showed resistance floating anywhere from 900-ohms to 100-ohms, and sometimes would trigger the BEEP on the continuity test.
WTF?
I took the MOMO horn button apart, and it looks like all brass parts in there.
The center contact point on the bottom looked pretty dull, so I just sanded to a nice shiny surface - this fixed the intermittent contact problem.
So it looks like these MOMO horn button assemblies are not that reliable.
For the record, I run a MOMO Race 350mm, and it has been installed in the car for about 7 years now.
It has been through Sacramento, CA summers / winters...Las Vegas, NV summers / winters...and Hawaii humidity.
If you're running a MOMO horn button and getting problems with the horn, you might want to check the button itself!
Through all this troubleshooting, I rewired the horn circuit to a dedicated Bosch relay and bypassed all the stock crap - the wiring runs through the blasted "CPU".
Hope this helps!
-Ted
04-19-06, 11:32 AM
#4
Senior Member
The right rear brake on my Audi did the same thing as yours a few months back. It turned out that one of the caliper pins siezed due to a faulty rubber boot. The piston-actuated inboard pad was releasing correctly, but the outboard pad was constantly being held in firm contact with the rotor. It wore to the backing plate, and the other three rear pads still looked brand new. Luckily, those brakes had squeal shims.
I know you're thorough, and that you checked your calipers and ensured that the floating parts float freely, but the problem you describe sure sounds like a siezed caliper--especially since it was an outboard pad. Maybe the pad ears were siezed in the grooves that they slide back and forth in?
I hope I don't sound like I'm second-guessing; I know you're a pro, and a much more experience mechanic than me. I just have a natural curosity, since I once experienced the same problem.
I know you're thorough, and that you checked your calipers and ensured that the floating parts float freely, but the problem you describe sure sounds like a siezed caliper--especially since it was an outboard pad. Maybe the pad ears were siezed in the grooves that they slide back and forth in?
I hope I don't sound like I'm second-guessing; I know you're a pro, and a much more experience mechanic than me. I just have a natural curosity, since I once experienced the same problem.
04-19-06, 10:47 PM
#5
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Thread Starter
Originally Posted by bigdv519
What brand of brake pads do you guys get out there?
Since the rotors is basically no good, this is my DD, so I needed it up and running.
I'll be running upgrade pads soon - looking at the Project Mu stuff on eBay.
Also, can you post pics of the steering wheel?
In fact, it looks butt-ugly right now cause I have a custom spacer in there and a custom trim ring was made to make everything work.
Just so the cops don't get suspicious, I slapped the Mazda steering wheel button back on so it just says "MAZDA" on it.
-Ted
04-19-06, 10:48 PM
#6
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Thread Starter
Originally Posted by carsaregood
cool, good to know the momo horn button issue. i've only had mine on for a few months, but maybe in 5 years hopefully i'll remember to check the contacts!
This was not something I expected since I paid $200+ for this MOMO wheel! :P
-Ted
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04-19-06, 10:50 PM
#8
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Thread Starter
Originally Posted by buttsjim
The right rear brake on my Audi did the same thing as yours a few months back. It turned out that one of the caliper pins siezed due to a faulty rubber boot. The piston-actuated inboard pad was releasing correctly, but the outboard pad was constantly being held in firm contact with the rotor. It wore to the backing plate, and the other three rear pads still looked brand new. Luckily, those brakes had squeal shims.
I know you're thorough, and that you checked your calipers and ensured that the floating parts float freely, but the problem you describe sure sounds like a siezed caliper--especially since it was an outboard pad. Maybe the pad ears were siezed in the grooves that they slide back and forth in?
I hope I don't sound like I'm second-guessing; I know you're a pro, and a much more experience mechanic than me. I just have a natural curosity, since I once experienced the same problem.
I know you're thorough, and that you checked your calipers and ensured that the floating parts float freely, but the problem you describe sure sounds like a siezed caliper--especially since it was an outboard pad. Maybe the pad ears were siezed in the grooves that they slide back and forth in?
I hope I don't sound like I'm second-guessing; I know you're a pro, and a much more experience mechanic than me. I just have a natural curosity, since I once experienced the same problem.
I was totally expecting to find a seized caliper back there.
I just did a real quick inspection and only managed to slide everything around for just a few minutes before I slapped everything back together.
I needed the car back up and running, and time was tight.
I'll need to go back under there soon and redo everything since I reran old pads on the bad rotor; I didn't want to waste brand new brake pads on the bad rotor, so I used the old pads to maybe get the grooving down a bit.
When I go back under, I'll do a more thorough inspection within a few weeks.
Thanx for the insight!
-Ted
04-19-06, 10:52 PM
#9
tom port.. AKA streetport
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hmmmmm....
im having the same brake problems and im getting the exact same brakes tommorow morning...
hahhaha
its not sounding to good back their thats for sure so its been sitting in my drive way waiting on brakes...
im having the same brake problems and im getting the exact same brakes tommorow morning...
hahhaha
its not sounding to good back their thats for sure so its been sitting in my drive way waiting on brakes...
04-20-06, 01:09 AM
#10
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Originally Posted by Jager
Why don't you ever post pictures of your car Ted?
Do you need me to show up in Hawaii and take em for the rest of us?
Do you need me to show up in Hawaii and take em for the rest of us?
I'm sure once pics pop up, you're going to see a lot of photochop captions with my car all over the place.
Once I get the wheels pics all taken care of, maybe I'll think about putting up real pics at the same time.
-Ted
04-20-06, 06:38 AM
#11
Mr. Nice Guy
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Speaking as an ex-counterman at a fiew auto parts stores, I can say that it is not that uncommon to have dissimilar wear on your pads from inside to out. Believe it or not, even the way the rubber brake line is routed can effect the way the pads wear. Under "no braking" situations, the caliper can actually be pushed or pulled in one direction or the other by just the flex tension of the brake line, causing one pad to ware slightly faster than the other. Even with optimal break performance.
As for the dirty brass contacts, did you use any dielectric grease when you reassembled the horn button? It will save you from having to do the dirty deed again.
As for the dirty brass contacts, did you use any dielectric grease when you reassembled the horn button? It will save you from having to do the dirty deed again.
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