Fast vibration in rear under light braking - new pads & rotors

94MEdition · 07-12-2010, 11:07 PM

Just put new pads and rotors on this weekend and after bedding them... I notice a strong, very fast vibration in the rear under light braking. For example, if I brake hard from 80MPH to 40MPH, no vibration. If I brake hard from 40MPH to 10MPH, as I approach 15 MPH and really let off the brake to arrive at 10MPH, I get this sudden and very rapid vibration. I can repeat it almost consistently when braking with soft application to the brake pedal when going under 20 MPH and slowing to 0 slowly.

No clue what this is, has anyone else experienced it? Any tips?

New NAPA rotors with Axxis Ultimate pads.
1994 Miata

Thanks!
Joseph

howangsNA · 07-12-2010, 11:52 PM

Check ur lug nuts are you using the brake hardware in the rear?

94MEdition · 07-13-2010, 07:38 AM

I have a feeling when I picked it up from the shop I saw the old M shaped retractor springs or maybe it was just the pad shims sitting in the box of replacement parts. Figured he probably put new ones on, but now I have a feeling he may not have and just left them off.

If that's what you're talking about, I'd have to double check. Could those M shaped retractor springs or pad shims lacking from the rear brakes cause it?

Searched and am seeing varied answers on those M shaped retractor springs/shims really making the difference. Can those be reused from the old set of pads or should I get a new set?

Thanks tons!!

nannerpus · 07-13-2010, 08:23 AM

Have the shop solve the problem they caused.

94MEdition · 07-13-2010, 08:26 AM

Quote:

Originally Posted by nannerpus

Have the shop solve the problem they caused.

Agreed, though it is about 35 minutes away and if I can jack the car up here, fix the problem, I'd rather be safer than tow/drive it there and create a problem.

94MEdition · 07-13-2010, 08:41 AM

Just spoke with the mechanic, he said only 1 m shaped retractor spring was on the car (passenger side) and when he reinstalled the new brakes he left it with only 1 m shaped retractor spring.

Now I'm scratching my head and on the hunt for another set of m shaped retractor springs, please let me know if you any you can ship to Boca Raton, FL - 33486.

Dealer does not sell it separately.

atx miata · 07-13-2010, 12:11 PM

I have ordered a set of the clips only from Autozone. Broke one when I was changing pads.

94MEdition · 07-15-2010, 04:45 PM

Quote:

Originally Posted by atx miata

I have ordered a set of the clips only from Autozone. Broke one when I was changing pads.

Just called them, $9.99 for the set from Advance Auto Parts.

Should be able to jack the car up and put them in tomorrow morning. We'll see what happens.

techie · 07-15-2010, 11:00 PM

werid...i just use the main brake clips not the shims and mine seems fine

94MEdition · 07-15-2010, 11:41 PM

Quote:

Originally Posted by techie

werid...i just use the main brake clips not the shims and mine seems fine

Yeah... I've heard the same thing a few times too... but I think it's the fact that it currently has 2 m shaped springs on the passenger side caliper and 0 m shaped springs on the driver's side... essentially only 2 of its 4 m shaped springs are on the car. This causes one hell of a vibration.

Calling the dealer to get the right parts and do the job right asap.

94MEdition · 07-21-2010, 11:51 AM

Updating this thread, may help someone down the road.

Mazda dealership had the right parts for the job, front and rear brake hardware kit part numbers:

For 1.8L:
NAY5-33-29Z -MV (Front)
BCYF-26-49ZA-MV (Rear)

$10 and $5 for the parts.

Put the rear hardware on this morning and tightened everything up. No more vibration.

07-12-2010, 11:07 PM	#1 (permalink)
94MEdition Member Join Date: Nov 2007 Location: South Florida - Boca Raton, FL Posts: 159	Fast vibration in rear under light braking - new pads & rotors Just put new pads and rotors on this weekend and after bedding them... I notice a strong, very fast vibration in the rear under light braking. For example, if I brake hard from 80MPH to 40MPH, no vibration. If I brake hard from 40MPH to 10MPH, as I approach 15 MPH and really let off the brake to arrive at 10MPH, I get this sudden and very rapid vibration. I can repeat it almost consistently when braking with soft application to the brake pedal when going under 20 MPH and slowing to 0 slowly. No clue what this is, has anyone else experienced it? Any tips? New NAPA rotors with Axxis Ultimate pads. 1994 Miata Thanks! Joseph
	__________________ Joseph 1994 M Edition - HDHCDD, Stance GR+, RT615s, Racing Beat 4-2-1, 3" Mandrel Bent Catless Header-Back, Timing @ 14*, Sparco D-Cut 280MM, and more... 2008 Passat 2.0T TSI 6Spd Manual

07-12-2010, 11:52 PM	#2 (permalink)
howangsNA Member Join Date: Mar 2008 Location: Yes Homo/Man Francisco, CA Posts: 1,161	Re: Fast vibration in rear under light braking - new pads & rotors Check ur lug nuts are you using the brake hardware in the rear?
	__________________ TeAm HeRrA fRuSh

07-13-2010, 07:38 AM	#3 (permalink)
94MEdition Member Join Date: Nov 2007 Location: South Florida - Boca Raton, FL Posts: 159	Re: Fast vibration in rear under light braking - new pads & rotors I have a feeling when I picked it up from the shop I saw the old M shaped retractor springs or maybe it was just the pad shims sitting in the box of replacement parts. Figured he probably put new ones on, but now I have a feeling he may not have and just left them off. If that's what you're talking about, I'd have to double check. Could those M shaped retractor springs or pad shims lacking from the rear brakes cause it? Searched and am seeing varied answers on those M shaped retractor springs/shims really making the difference. Can those be reused from the old set of pads or should I get a new set? Thanks tons!!
	__________________ Joseph 1994 M Edition - HDHCDD, Stance GR+, RT615s, Racing Beat 4-2-1, 3" Mandrel Bent Catless Header-Back, Timing @ 14, Sparco D-Cut 280MM, and more... 2008 Passat 2.0T TSI 6Spd Manual Last edited by 94MEdition; 07-13-2010 at 08:12 AM.*

07-13-2010, 08:23 AM	#4 (permalink)
nannerpus ┐('～`；)┌ Join Date: Jan 2007 Location: Texas. Posts: 6,215	Re: Fast vibration in rear under light braking - new pads & rotors Have the shop solve the problem they caused.

07-13-2010, 08:41 AM	#6 (permalink)
94MEdition Member Join Date: Nov 2007 Location: South Florida - Boca Raton, FL Posts: 159	Re: Fast vibration in rear under light braking - new pads & rotors Just spoke with the mechanic, he said only 1 m shaped retractor spring was on the car (passenger side) and when he reinstalled the new brakes he left it with only 1 m shaped retractor spring. Now I'm scratching my head and on the hunt for another set of m shaped retractor springs, please let me know if you any you can ship to Boca Raton, FL - 33486. Dealer does not sell it separately.
	__________________ Joseph 1994 M Edition - HDHCDD, Stance GR+, RT615s, Racing Beat 4-2-1, 3" Mandrel Bent Catless Header-Back, Timing @ 14*, Sparco D-Cut 280MM, and more... 2008 Passat 2.0T TSI 6Spd Manual

07-13-2010, 12:11 PM	#7 (permalink)
atx miata Member Join Date: Apr 2010 Location: Austin, TX Posts: 157	Re: Fast vibration in rear under light braking - new pads & rotors I have ordered a set of the clips only from Autozone. Broke one when I was changing pads.

07-15-2010, 11:00 PM	#9 (permalink)
techie Member Join Date: May 2007 Location: Fairfax Va Posts: 201	Re: Fast vibration in rear under light braking - new pads & rotors werid...i just use the main brake clips not the shims and mine seems fine
	__________________ http://sphotos.ak.fbcdn.net/hphotos-..._3397107_n.jpg WTB-Red Finsh Panel

07-21-2010, 11:51 AM	#11 (permalink)
94MEdition Member Join Date: Nov 2007 Location: South Florida - Boca Raton, FL Posts: 159	Re: Fast vibration in rear under light braking - new pads & rotors Updating this thread, may help someone down the road. Mazda dealership had the right parts for the job, front and rear brake hardware kit part numbers: For 1.8L: NAY5-33-29Z -MV (Front) BCYF-26-49ZA-MV (Rear) $10 and $5 for the parts. Put the rear hardware on this morning and tightened everything up. No more vibration.
	__________________ Joseph 1994 M Edition - HDHCDD, Stance GR+, RT615s, Racing Beat 4-2-1, 3" Mandrel Bent Catless Header-Back, Timing @ 14*, Sparco D-Cut 280MM, and more... 2008 Passat 2.0T TSI 6Spd Manual

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