Groaning rear brakes

[richardu]

My Unique is about three years old. I've had a great first summer running my car in a nearly fully sorted out condition. But I still have a couple of problems I'd like to solve. I've got rear brakes that let out a low groan when coming to a stop about 15-20% of the time. It happens sporatically, but it seems to be more pronounced when I run for at least several miles and then stop. I've played around with the brake bias a lot and my adjustment bar is loose. Still no change in the groan. I have read the various threads on brakes. I'm wondering if I may have gotten brake fluid on the rear pads, because I had a signifcant fitting leak a while back. I'm thinking about just changing the rear pads to see what happens. Does anyone have a brand name and part number for rear pads they would recommend? Also, I've got a car that stops adequately, but just barely. While I'm at it, I'd like to improve the braking performance of the car, even if its just a little bit. I've read that some guys are using pads with a higher coeficient of friction than the ones the Weavers typically install, and performance is better. Any help with some rear pad recommendations would be greatly appreciated.

Dick Untch

[TurnpikeBoy]

Great fun. Always exciting to find out just how much leg non-power brakes take, especially after we've been spoiled by power brakes for the last 4 decades.

If you got fluid on the rear pads, not much you can do but replace them. And if in doubt, replace 'em anyway. I put standard Jag pads into mine when the origs wore out, and cannot say they're really deficient in any way. I CAN lock up the rears, but really have to want to - otherwise, the car just flat stops.

This is, however, a consequence of changing out the front pads too. The original Wilwood pads were awful hard and a looong way short of confidence building. I bought Hawk HPS pads, part #HB100F.480, and apart from dust on the wheels, am extremely satisfied with the results. These changed my mind about the adequacy of the brakes - it now feels like I can stand the car on its' nose, and without getting leg cramps. Brake performance is now, all around, just as spectacular as the rest of the car.

There are certainly lots of alternatives, including Wilwood pads, which others on here have tried and very much liked. Pays yer money and takes yer choices - but the potential for improvement is there, and in spades. Good luck, you will find what you need!



-Roger

[JeepSnake]

Dick,

When we first got our 289 (used) it squeaked & groaned in the rear when coming to a stop. Knowing that it had been driven little, I lightly held my foot on the brake for several miles to let the pads scrub rust off the rotors and heat everything thoroughly. It didn't take long for the noise to go away.

On other vehicles, I have pulled the pads & rotors and basically just deglazed both with success. This consists of going over the surfaces with a Scotchbrite disc on a small rotary air sander. And yes, I did rough up the friction material on the pads this way to break the glaze. Just wear eye protection and a decent respirator. (Keep in mind this is on typical production pads, which have friction material over twice as thick as our Cobra pads, and hence last many more miles. On the Cobra, I'd just get new pads.)

As far as effort, the top thing you can do is break the pads in via the instructions on this web site (search will turn them up).

Another note about effort. I discovered that a great deal of the "poor braking" on these cars is a perception issue (at least it was to me). With the factory Wilwood pedal setup, I literally felt like I was going to push the pedal through the floor before the car would stop. Anyhow, I wanted to raise the brake pedal anyway, so I made up some extended clevises and installed them on the balance bar. The pedal came right up, and HOLY COW! The car stops so much better!

Now, I know good and well that raising the pedal didn't actually change the amount of leg effort required to stop. BUT - it put the pedal in a position that I am more naturally comfortable with. It now "feels" like the pedal in my Jeep, in my Chevelle, even like the one on our John Deere tractor! This feel is familiar to my leg, and so the PERCEPTION is that the braking is now much easier. Sure, the pedal position would be lousy for a real race driver who likes to heel-toe. But, I aren't one of those guys.

Anyhow, just some thoughts that might help.

[richardu]

Thanks for the responses Roger and Zach! Before going to roughing up the surfaces of the rotors for better braking performance, I would probably first try going with the Hawk pads in front and the Jag pads in the rear. Are the Jag pads readily available at regular Jag dealerships, or are there other sources I need to pursue? When hunting for parts during my build, part numbers really helped. Do you happen to have the part number for the rear Jag pads?

DU

[TurnpikeBoy]

Believe it or not, I got the Jag pads off eBay (!). A warehouse, I presume, named www.captainjaguarscathouse.com - their part #JLM-1513. I'm sure about anybody can sell 'em to you. $34 to the door; don't remember brand off hand, but box said made in jolly ol' England. If you do some shopping, you might find them cheaper. I figured I'd spend more on the fronts since they carry more of the load.

Take heart, bro - that Cobra is going to stop hard enough to pull the fillings outta your teeth. And stick with street-type pads on Wilwoods or Hawks or whatever. Pads made for more sporting use (race, auto-x, etc) generally work best at higher temps, which means you gotta get them HOT before they really want to pitch you thru the windshield. Street pads are designed to work when cooled off - yeah, it makes a BIG difference!



-Roger

[richardu]

Thanks Roger for the advice and the source for the rear jag brake pads. I'll let you know how things turn out. I'm anxious to make the pad change and get some more driving in before the snow flies.


DU

[Jerry Cowing]

You might want to try these.

BrakeTru® On-The-Car RotorResurfacer pads are new single use tools that cut the time to perform a complete brake job to 30 minutes or less. They eliminate the difficult job of removing the rotors from the car for machining.

At the heart of Brake Tru RotorResurfacers are rugged tool grade ceramic abrasives bonded to a fiberboard backing.

To use, the RotorResurfacers are adhered to the face of each worn brake pad.
With one wheel raised and removed, the pads are inserted into the brake calipers. The vehicle is put in gear and accelerated to about 3,000 rpm (30 mph on the speedometer).

Resurfacing occurs when the brake pedal is applied for two cycles of two-seconds each. The worn brake pads with the RotorResurfacers are then removed and discarded. New brake pads are installed to complete the job. The process is repeated on the other front wheel.

[TurnpikeBoy]

Sounds like it would work neat, especially for those tough-to-get-to rear rotors.

Might be a smidge more difficult on the fronts, tho