Brakes pulsing

[Stumpy6Guns]

My brake pedal pulses as I slow down, and the harder I stop the harder the pulsing. It's not the fast pulsing you get from an ABS system - it seems to match wheel speed. I can't tell if it's front or rear. It feels like either a warped rotor or uneven material transfer to the rotor, so I tried to bed them in with five or six hard stops in succession from 60 - 15 mph. It didn't make any difference. This is on dry pavement; it hasn't rained here in months.
I suppose I could pull the rotors and lay them on a surface plate to check flatness and examine the surfaces. If they're warped I'll replace them, but I would rather avoid the expense.

Has anyone else had this problem? How did you find the cure, and what was it?

 

[Stumpy6Guns]

Well, never mind.

I took a good look at the front rotors tonight. The right rotor has an uneven pattern of score marks, indicating the presence of runout. My floor jack doesn't fit under the bike, so I can't get the wheels off the ground. Looks like a trip to Harbor Freight is in order.

I'm going to replace the front rotors and pads. I'm a big fan of EBC brake pads, so I'll get greenstuff or yellowstuff if they make it. Not sure about rotors yet.

 

[Peter Aawen]

It sure sounds like it's the rotors!! Might pay to get them checked & if they aren't true, then either get them 'machined true' or replaced.... Then when you refit/fit them, install your choice of replacement brake pads too. :thumbup:

 

[irvin48]

baja ron has good prices on them.

 

[Stumpy6Guns]

I placed the order with Ron today, so I should be able to change them this weekend. One little problem, though - my floor jack doesn't fit under the Spyder, so is it OK to use ramps instead? :joke:

 

[spyderbitten]

I placed the order with Ron today, so I should be able to change them this weekend. One little problem, though - my floor jack doesn't fit under the Spyder, so is it OK to use ramps instead? :joke:

Drive Spyder up on a couple 2x4 blocks to gain clearance for floor jack.

 

[Stumpy6Guns]

Drive Spyder up on a couple 2x4 blocks to gain clearance for floor jack.

That didn't even occur to me! Thanks- you just saved me 80 bucks!

 

[Stumpy6Guns]

Changed the brakes today

My new EBC pads and rotors came in yesterday (Thanks, Ron!), so this morning I installed them. It took me longer than I anticipated because of the clips on the backs of the pads, and just because this was my first brake job on the Spyder.
The torque on the lug nuts was uneven, with one so tight that I lifted the left tire off the ground. Definitely overtorqued. Others were more reasonable.
After I jacked it up and put safety stands in place, and got the tires off, the brake assembly was very accessible. 2 caliper bolts out, and the caliper and rotor came right off. I popped the pads out, and used a 4" C-clamp to compress the pistons into the caliper.
Then the fun began. I used a utility knife to separate the backplate from each of the old pads. There was a contact adhesive holding them together that had to be cut through, so I slid the blade into the joint and opened the gap enough to get a small screwdriver in to pry it open.

The clips are from Satan's workshop! :cus: I tried every pair of pliers I have, and just couldn't squeeze the clip together and lift the clip out of the hooks that hold them. Ultimately, a pair of snap-ring pliers saved the day. I was able to seat the pins of the pliers into the clip ends, and it gave me enough daylight that I could slip a small 1/8" flat screwdriver tip in and lever the clip out. The first clip took me an hour and a half to figure out; the rest of them went really fast because I had a technique that worked well. Same learning curve on installing the clips onto the new pads- went through all the pliers, and the snap-ring pliers were the only pliers that worked. Squeeze the clip ends together, put the clip on the pad and push down with thumb, and release.

The gap between the new pads was a little tight on the left side and I had to use a small dead-blow mallet to get the caliper on to the rotor. I didn't clobber the thing; a little tappity-tap did the trick.
18 lbf/ft on the caliper bolts, 77 lbf/ft torque on the lug nuts, checked brake fluid levels, and now it is ready to test. :spyder:I'll have to wait until tomorrow, though. This afternoon was taken with other stuff.

The old OEM rotor on the right has about .005" of runout. Max warp allowed is .004", so this rotor was definitely out-of-spec.

 

[Stumpy6Guns]

Follow-up on brake job

First, the tabs on the pads go DOWN! Amazing how things fit better when they are put together properly. In this case, it was the left side, and I caught it before I took the bike for a test, so no harm.

Everything is so much smoother now. There is no pulsing, and now that the pads are bedded in, it stops like it is supposed to.

 

[Bob Denman]

:clap: Thanks for the update. :thumbup: I'm glad to hear that the pulsing is now history! :yes:

 

[BajaRon]

My brake pedal pulses as I slow down, and the harder I stop the harder the pulsing. It's not the fast pulsing you get from an ABS system - it seems to match wheel speed. I can't tell if it's front or rear. It feels like either a warped rotor or uneven material transfer to the rotor, so I tried to bed them in with five or six hard stops in succession from 60 - 15 mph. It didn't make any difference. This is on dry pavement; it hasn't rained here in months.
I suppose I could pull the rotors and lay them on a surface plate to check flatness and examine the surfaces. If they're warped I'll replace them, but I would rather avoid the expense.

Has anyone else had this problem? How did you find the cure, and what was it?

I had this same issue with my Spyder. Turned out to be 1 bad ball joint and bad A-Arm bushings. It sure felt like a warped rotor to me. But it wasn't. At least in my case.