Front brake judder

[shudnobetter]

I've a fairly stock 1990 3cv showing 50,000 on the clock. The front brakes are not fantastic...hoses are s/s braided. Main issue is a judder when braking which I assumed is a damaged/warped disc. I don't want to shell out for new discs and pads without being certain, but want to sort it if at all possible.
What should I check first to eliminate potential causes?
Any advice welcome.
Thank you.

I'd posted this in Mods by mistake and re-posted here cos I couldn't see how to move it to the correct category.

[chiz]

This problem immediately cropped up as soon as I put on a set of gold dot calipers.1200 lower fork legs,17'' front wheel, braided lines, front brake master and a couple of used floating discs. I have never been able to solve the problem, though I have certainly tried....Good luck Lez

[Old Rider]

I could be that you have  lose stearinghead bearings .Try also to spin frontwheel to see if its running easy.

[FJmonkey]

I'd posted this in Mods by mistake and re-posted here cos I couldn't see how to move it to the correct category.

[Post in mods section has been removed.]

[giantkiller]

I could be that you have  lose stearinghead bearings .Try also to spin frontwheel to see if its running easy.

Check the steering stem first... I've had it be loose stem. It's a hard compromise to. Find the right tightness.between low speed wander (too tight) and brake jutter (too loose) I think the stiffness of the gsxr inverted front ends I have on my bikes. Magnifies this. That being said I've had warped discs also. Will's rim repair. Actually straighens bike rims and disc's been awhile since I've used his services. Hope he's still in business.

[Pat Conlon]

A timely question, I too am chasing a shudder.
I had 2001 R-1 blue spots on my '84 and all was well (14mm m/c, Spiegler lines, HH pads, DOT 5 fluid, Galfer wave rotors))
Braking was smooth and strong with excellent modulation. Light years better than oem.

Moditius kicks in....I changed over to the 2003 YZF R-1 Gold spots with new HH pads, and now I have a shudder. Hmmmm, what to do?

Always start with clean rotors. Scrub off all the old transfer layers that builds up on the rotors. Easy to do with my cordless drill and one of these:


No help?

Isolate the problem. Figure out which side is the problem and if the problem is the caliper or rotor.
1) Detach right side caliper (leave line attached) and zip tie it up and out of the way, go for a ride. Result: Shudder is gone.
2) Detach left side caliper, zip tie and ride (reattach right caliper)...yep shudder returns, so something is going on with the right side....but is it the caliper or rotor?
3) Dismount front wheel and switch sides on the (clean) brake rotors...see if the shudder follows the rotor to the left side (opposite side)
Result: With rotors swapped, the shudder remains on the right side....so it's the right side caliper.

Time for new seals...see if that helps. Also, with the caliper pistons out, it's a good time to clean out all the old DOT 3 residue in the caliper.
When doing new seals, I always do both calipers.

Results pending...stayed tuned.

[chiz]

Any love yet? Just a note about my car  was suffering for about a year and a half with the same problem, changed 3 sets of rotors up front with no joy. The parts store  guy said I was doing it wrong. Sold me over $200 in pads and rotors said they would do the trick, even offered to take the parts back.
     I told him I thought he was full of it... Went back a day later and had to shake his hand.
  Lez

[Pat Conlon]

Gonna have to wait for my results. I'm outta the desert until November.

[FJ_Hooligan]

Any love yet? Just a note about my car  was suffering for about a year and a half with the same problem, changed 3 sets of rotors up front with no joy. The parts store  guy said I was doing it wrong. Sold me over $200 in pads and rotors said they would do the trick, even offered to take the parts back.
     I told him I thought he was full of it... Went back a day later and had to shake his hand.
  Lez

I don't get it. 
What were you doing wrong?  Using the wrong parts?

[FJ_Hooligan]

On my FZ1, I have a front brake chatter (which I suppose could also be considered a judder). 

Felt just like the steering head bearings were loose.  They were NOT.  Also not a warped rotor.

I doesn't do it all the time, seems to be only when getting on the brake lever fairly hard.  Not a full on panic stop, but more a case of catching a light turning red unexpectedly.

It doesn't do it all through the braking action, the chatter happens for a few seconds before I'm totally stopped.

[Pat Conlon]

What I don't understand is why was everything fine (like really really good) with '01 blue spots, then the shudder appears the moment I put the '03 gold spots on....(the shudder is very light just like Hooli's)
I used new pads on the goldies. Gotta be something with the seals on the right caliper.
No obvious leaks.

[ZOA NOM]

I have yet to see a warped rotor on any vehicle I drive, including my race car. Pads, lines, calipers, master, in that order is my experience.

[chiz]

Any love yet? Just a note about my car  was suffering for about a year and a half with the same problem, changed 3 sets of rotors up front with no joy. The parts store  guy said I was doing it wrong. Sold me over $200 in pads and rotors said they would do the trick, even offered to take the parts back.
     I told him I thought he was full of it... Went back a day later and had to shake his hand.
  Lez

I don't get it. 
What were you doing wrong?  Using the wrong parts?

The part;s wer'nt wrong per say, they just were not the parts of proper construction or materials that was best suited to this VW  Jetta. They fit fine and were not cheap but for some reason not really explained properly the fourth set of rotors and pads were the cats meow.
Lez

[giantkiller]

I have yet to see a warped rotor on any vehicle I drive, including my race car. Pads, lines, calipers, master, in that order is my experience.

The ones I had straighten. I think got slightly bent in shipping. So weren't really warped. 2 sets. One new. One set came on gsxr wheel. On balancing stand could see the movement. After I took the wheels off.
Had another set of stock rotors that had a small amount of slop in the float rivets? Not sure if you can call them rivets. I couldn't feel it. But Will said it was there and sent them back. Like I said I think the stiffness of the inverted front ends make it more pronounced.

[shudnobetter]

A timely question, I too am chasing a shudder.
I had 2001 R-1 blue spots on my '84 and all was well (14mm m/c, Spiegler lines, HH pads, DOT 5 fluid, Galfer wave rotors))
Braking was smooth and strong with excellent modulation. Light years better than oem.

Moditius kicks in....I changed over to the 2003 YZF R-1 Gold spots with new HH pads, and now I have a shudder. Hmmmm, what to do?

Always start with clean rotors. Scrub off all the old transfer layers that builds up on the rotors. Easy to do with my cordless drill and one of these:


No help?

Isolate the problem. Figure out which side is the problem and if the problem is the caliper or rotor.
1) Detach right side caliper (leave line attached) and zip tie it up and out of the way, go for a ride. Result: Shudder is gone.
2) Detach left side caliper, zip tie and ride (reattach right caliper)...yep shudder returns, so something is going on with the right side....but is it the caliper or rotor?
3) Dismount front wheel and switch sides on the (clean) brake rotors...see if the shudder follows the rotor to the left side (opposite side)
Result: With rotors swapped, the shudder remains on the right side....so it's the right side caliper.

Time for new seals...see if that helps. Also, with the caliper pistons out, it's a good time to clean out all the old DOT 3 residue in the caliper.
When doing new seals, I always do both calipers.

Results pending...stayed tuned.

Update. Steering etc all seems ok. Decided to take the plunge and do a full brake upgrade. r1 calipers and new discs. These are now fitted. Just need to upgrade the m/c now to a fj1300 version. Do I need to use a FJR1300 brake lever with this?