pulsating brakes

[88cougar]

Hi all.

You have all been a great help in the past so I hope you can help now. I just finished doing all 4 brakes with new pads and rotors. Now when I brake from 40mph and above my brakes pulsate. It doesn't happen at slower speeds. Also, when I am stopped at a light it pulsates. So far I have checked the rotors and they are not warped. I lubed the slider pins, and torqued the caliper bolts along with locktite. I also pulled the abs fuse and it is still there. What am I missing? Could it be the caliper pistons? I really appreciate any input.

Thanks all.

 

[trucku]

have no idea, but free bump for you.

 

[jlsparky7]

The rubber part of the brake lines might be "bubbling".

 

[vroomzoomboom]

maybe there is some scale on your hubs between the wheel studs? try wire brushing them and see if that helps. just a thought.

 

[Heavymentill]

You could have warped rotors or inproperly torqued wheel lugs. If your rotors are only slightly warped they may corrected by machining them on a brake lathe.

 

[88cougar]

Thanks for the quick responses.

Vroomboomzoom: Already done. Sorry I should have said that in my original post.

Heavymentill: Rotors are fine. Checked with a runout gauge.

jlsparky: Thanks. Visual inspection of the lines shows nothing but I will replace them anyway. I am going to put in rebuilt calipers as well.

 

[Heavymentill]

Did you measure the rotor in 5 equally spaced locations? Measurements should be within 0.005"

 

[88cougar]

measurements done by a machine shop where they turn rotors. They said everything in spec to .001. I trust them.

 

[88cougar]

Problem solved!

Apparently, when I re-installed my calipers I twisted the brake line. I just had to re-install them correctly and the problem went away. Just proves the adage that a little knowledge is dangerous. I only hope this helps someone else from making the same mistake I did. Thanks to all for the help.

 

[trucku]

Good to hear.

Hopefully the twist you put in the line has not damaged it. You might want to change it out for good measure, so it does not fail on you down the road.