pulsation while braking, sometimes.
12-20-14, 04:31 PM
#1
Pole Position
Thread Starter
pulsation while braking, sometimes.
What could cause this? Its coming from the rear end. It seems to happen if I am going over 45mph and apply the brakes. It feels like a warped rotor, but if braking from 40mph and below, it is smooth. Both rear wheel bearings have been replaced. Tires are new. There was a vibration while cruising between 40&50mph, which was ”cured” by the new tires... While replacing the wheel bearing, I noticed some play in the right rear axle at the joint closest to the wheel. Any suggestions?
12-22-14, 08:43 AM
#3
Wheels out of balance will vibrate ALWAYS (and get worse with speed). It will NEVER come and go. Fix a Flat will come and go rhythmically. (and hence drive you batty)
Note if the pulsation is when brakes are cold or warm/hot. Mine did it much more pronounced when they were cold.
Cheap fix, take rotors off, inspect the INSIDE and remove the rotor material from the inside rotor surface. Common issue. Use sanding disk or sand paper. Keep in circles. Don't dig grooves.
You can't do it perfect like a machine, but you won't ever feel it anyways, you would be hard pressed to dig that hard into the rotor surface.
Axles vibrate based on LOAD, so if a CV joint or U-Joint or axle related issue, it will be LOAD related.
Tie rods will cause issues as the different speeds cause different loads on the worn tie rod and cause it to change alignment as you drive. The more toe in/out you get can cause very irregular alignment and cause issues. And braking will usually cause a pull.
Warped rotors are very much a VERY VERY RARE occurrence. It would be a last step. Not a first step to look at. From what you describe brake pad material has deposited on one or more of the rotors.
Note if the pulsation is when brakes are cold or warm/hot. Mine did it much more pronounced when they were cold.
Cheap fix, take rotors off, inspect the INSIDE and remove the rotor material from the inside rotor surface. Common issue. Use sanding disk or sand paper. Keep in circles. Don't dig grooves.
You can't do it perfect like a machine, but you won't ever feel it anyways, you would be hard pressed to dig that hard into the rotor surface.
Axles vibrate based on LOAD, so if a CV joint or U-Joint or axle related issue, it will be LOAD related.
Tie rods will cause issues as the different speeds cause different loads on the worn tie rod and cause it to change alignment as you drive. The more toe in/out you get can cause very irregular alignment and cause issues. And braking will usually cause a pull.
Warped rotors are very much a VERY VERY RARE occurrence. It would be a last step. Not a first step to look at. From what you describe brake pad material has deposited on one or more of the rotors.
Last edited by RamAirRckt; 12-22-14 at 08:46 AM.
12-22-14, 09:38 AM
#4
I had a similar situation, I could feel pulsation/vibration when braking but did not know where it was coming from. After driving the car in a long trip to Las Vegas I was able to duplicate the issue when stepping on the brakes. When I returned home I removed front and rear rotors and took them to a shop to get them turned. Brake pads where gone little over 50 percent so I replaced all pads while I was there, Problem solved!!.
12-22-14, 10:17 AM
#5
Pole Position
Thread Starter
Thanks for the reply. Pretty sure it is coming from the rear end. Can't feel it in the steering wheel. Csr doesn't pull. If I brake at say 35mph, it is smooth. If it were build up on rotors, wouldn't it be noticeable at all speeds? What if a caliper wasn't working correctly?
Wheels out of balance will vibrate ALWAYS (and get worse with speed). It will NEVER come and go. Fix a Flat will come and go rhythmically. (and hence drive you batty)
Note if the pulsation is when brakes are cold or warm/hot. Mine did it much more pronounced when they were cold.
Cheap fix, take rotors off, inspect the INSIDE and remove the rotor material from the inside rotor surface. Common issue. Use sanding disk or sand paper. Keep in circles. Don't dig grooves.
You can't do it perfect like a machine, but you won't ever feel it anyways, you would be hard pressed to dig that hard into the rotor surface.
Axles vibrate based on LOAD, so if a CV joint or U-Joint or axle related issue, it will be LOAD related.
Tie rods will cause issues as the different speeds cause different loads on the worn tie rod and cause it to change alignment as you drive. The more toe in/out you get can cause very irregular alignment and cause issues. And braking will usually cause a pull.
Warped rotors are very much a VERY VERY RARE occurrence. It would be a last step. Not a first step to look at. From what you describe brake pad material has deposited on one or more of the rotors.
Note if the pulsation is when brakes are cold or warm/hot. Mine did it much more pronounced when they were cold.
Cheap fix, take rotors off, inspect the INSIDE and remove the rotor material from the inside rotor surface. Common issue. Use sanding disk or sand paper. Keep in circles. Don't dig grooves.
You can't do it perfect like a machine, but you won't ever feel it anyways, you would be hard pressed to dig that hard into the rotor surface.
Axles vibrate based on LOAD, so if a CV joint or U-Joint or axle related issue, it will be LOAD related.
Tie rods will cause issues as the different speeds cause different loads on the worn tie rod and cause it to change alignment as you drive. The more toe in/out you get can cause very irregular alignment and cause issues. And braking will usually cause a pull.
Warped rotors are very much a VERY VERY RARE occurrence. It would be a last step. Not a first step to look at. From what you describe brake pad material has deposited on one or more of the rotors.
12-22-14, 10:25 AM
#6
I did have 1 piston of my 2 piston front caliper on my GS go bad that caused a heat vibration. It was terrible and got worse significantly with brake application.
The piston was completely stuck when I tried to get it to move in when I put on new pads.
Don't turn them for brake pad material. Just sand it off. You never want to take out metal off the rotor thickness for no reason. That does NOT require turning, just some sanding with a coarse sand paper or friction disc. Just clean it up good with brake cleaner when you are done. Friction discs are great but the debris if left behind can be very abrasive.
The piston was completely stuck when I tried to get it to move in when I put on new pads.
Don't turn them for brake pad material. Just sand it off. You never want to take out metal off the rotor thickness for no reason. That does NOT require turning, just some sanding with a coarse sand paper or friction disc. Just clean it up good with brake cleaner when you are done. Friction discs are great but the debris if left behind can be very abrasive.
12-22-14, 11:33 AM
#7
If there is build up on the rotors vibration could/will occur when applying the brakes.
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12-23-14, 07:19 PM
#9
Pole Position
Thread Starter
There is nothing obviously wrong with the suspension. The right side rotor could be warped. My test for flatness was setting them on my table saw(it is dead flat), and checking if the surfaces match up. Left side was good. Right side I could rock, just slightly. This might be the problem... I sanded both rotors anyway and put everything back together. We will see hiw she brakes tomorrow.
12-24-14, 08:37 AM
#10
Pole Position
Thread Starter
Cleaning up the rotors had no effect.
Edit: I spoke too soon. Just drove around for a bit. It is actually better. I'm going to see how it acts over the next couple of days....
Edit: I spoke too soon. Just drove around for a bit. It is actually better. I'm going to see how it acts over the next couple of days....
Last edited by LazarusLng; 12-24-14 at 02:17 PM.
12-31-14, 04:39 PM
#11
Pole Position
Thread Starter
I replaced the front rotors and the outer tie rods. Problem solved. One of the tie rod ends was leaking some grease. They both had more play then the new ones, but I don't think that they were contributing to the problem. Pretty sure it was the rotors all along.
01-01-15, 07:25 AM
#12
I've had rotors that would only pulse when hot. I had them turned twice and the pulsing would return after some miles - again only when they were hot. I finally replaced the rotors and problem solved. Who knows.
Something that I didn't know then is that over tightening lug nuts leads to warped rotors. Toyota with their 76 ft-lbs lug nut torque limit leads to warped rotors after a shop torques them all the way up to stupid. If your lug nuts are making a "crack!" sound when they're loosened then your shop has screwed up. I always ask for the lug nuts to be torqued manually and not with torque sticks. I also keep an inexpensive torque wrench handy and use it whenever I get one of my cars back from any shop.
The lug nuts are almost always over tightened by a lot except at Costco and I love Costco for this. They use a torque wrench on every car and they demand that you return in a week to have the lug nuts re-tightened. Now that's perfection.
Something that I didn't know then is that over tightening lug nuts leads to warped rotors. Toyota with their 76 ft-lbs lug nut torque limit leads to warped rotors after a shop torques them all the way up to stupid. If your lug nuts are making a "crack!" sound when they're loosened then your shop has screwed up. I always ask for the lug nuts to be torqued manually and not with torque sticks. I also keep an inexpensive torque wrench handy and use it whenever I get one of my cars back from any shop.
The lug nuts are almost always over tightened by a lot except at Costco and I love Costco for this. They use a torque wrench on every car and they demand that you return in a week to have the lug nuts re-tightened. Now that's perfection.
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