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Stock Brakes

Posted: Sun Aug 28, 2005 4:32 am
by Busdriver
Howdy all,

I bought my 1991 Legacy L AWD a month ago and noticed that the front brakepads were about 1/4inch left. So I ordered stock OEM pads for the front and back. Fronts went in really quick, (I love disc brakes, I'm used to VW Bus Drum brakes...) The back ones though were of different pad wear width, the RL set was about 1/4 in thinner than the RR!! Any ideas what this might be?? I put the old ones in again just in case I have to do something else first. I would like to put the new ones in this sunday, tomorrow...
Also the Chiltons manual says something about diconnecting the e-brake?!? It's in the car right now but I thougth that's what it said. Is it necessary to do anything with the e-brake besides leave it not pulled??
A couple more questions..
I did not open any of the lines, even when I pushed the pistons back into the calipers, no leakage at the filler by the master cylinder.. I did open the cap up there though... When I took the soobster for a quick test drive the pedal went all the way to the floor once, then I pushed it a couple more times and it got tight like always... Is this normal with no open lines??

I've heard lots of talk about seating the pads...
Is this necessary, why??, what is the correct way??
Last one..
Do I have to have the engine running when I want to bleed the brakes?? I'm planning on exchanging the fluid since I don't know when it was last done. I'll be using Valvoline S...
Sorry for the length and THANK YOU!!!
Busdriver turned soobster cruiser...

Posted: Sun Aug 28, 2005 4:41 am
by skid542
Welcome to the BBS.

The old pads having different wear thickness doesn't really mean much, someone before you might have just replaced one side at one point. The important thing is that the thickness is the same across the pad, ie. if it's 1/4" at one place, it should be everywhere on that pad. Provided that checks, throw your new ones on and don't worry.

The pedal going down isn't anything to be concerned about. When you pushed the piston back in it pushed the fluid out and back into the system/resevoir, the pedal going down was just the fluid needed to push the pistons back out and fill them. As long as you have plenty of fluid in your resevoir you have nothing to worry about.

Posted: Sun Aug 28, 2005 7:22 am
by Legacy777
The uneven pads is more then likely caused by a sticking caliper. You really should clean the caliper guide pins and re-grease them if you didn't.

The pedal went to the floor initially because you pushed the caliper pistons back in further then they normally are. So what you experienced is normal.

As for bleeding, you don't need to have the engine running. If I have stubborn air in the system when I open it up, I will sometimes run the engine because it creates more pressure in the lines and helps force the air to the calipers.

Posted: Sun Aug 28, 2005 8:13 am
by Busdriver
"You really should clean the caliper guide pins and re-grease them if you didn't."

Where do I find those? Is one of the guides where I loosened the bottom bolt to flip up the caliper? Do you usually do that with all guides front brakes and back everytime you change pads?

Thanks

Posted: Sun Aug 28, 2005 3:27 pm
by IronMonkeyL255
I do.

Posted: Sun Aug 28, 2005 5:33 pm
by Legacy777
Busdriver wrote:"You really should clean the caliper guide pins and re-grease them if you didn't."

Where do I find those? Is one of the guides where I loosened the bottom bolt to flip up the caliper? Do you usually do that with all guides front brakes and back everytime you change pads?

Thanks
You see the cylinder in this pic that's to the right of the bolt that holds the caliper to the bracket?
http://www.main.experiencetherave.com:8 ... P_3816.JPG

That is inside the rubber boot thing. That is the guide pin. That is what you need to check to see that it can move back and forth freely. If it feels stiff, or is stuck, you need to take it apart and clean it.

Posted: Sun Aug 28, 2005 7:17 pm
by Manarius
There are two things you should do when replacing rear brakes on these cars.

1. Open the top of the brake fluid reservoir before you begin.

2. Use the new brake to push the piston back in the caliper, so you'll be able to get the new brakes in there easily.

I can do rear brakes in 20 mins..tops.

Posted: Mon Aug 29, 2005 3:06 am
by Legacypusher
Re: Front brake pads. My old Chilton's says, "NOTE: Do not force the piston straight into the caliper bore. The piston is mounted on a threaded spindle which will bend under pressure."

I, of course, had changed my front pads twice using a C-clamp and a small block of wood to compress the pistons, just like on all my previous cars, before I noticed the note, but have noticed no problems since.

Sorry to sound stupid, but how exactly do you use the new pad to push the piston back into the caliper?

Posted: Mon Aug 29, 2005 3:22 am
by Manarius
Legacypusher wrote:Sorry to sound stupid, but how exactly do you use the new pad to push the piston back into the caliper?
Umm..I have this tool that is like a "plate on a screw." (Sorry for horrible terms...I'll take a picture some time)

Basically, I use the "plate on a screw" plus the new brake (or old) to push the piston back into the caliper. I don't see any problem with using the C-Clamp...but I can hardly believe that the front caliper is a screw that you can damage from pushing it in.

Posted: Mon Aug 29, 2005 3:48 am
by Legacypusher
I'd love to see a photo of the "plate on a screw." It sounds intriguing. Chilton's also advises to "Release the parking brake and disconnect the cable from the caliper lever." And this is for changing the front pads. Hmmm.

I am quoting these passages from a big hardback copy of "Chilton's Import Car Manual, 1989-1993," that I bought for $1 at my library's overstock book sale. Looks like I got my money's worth. It was a big help when I changed my timing belt, though.

Posted: Mon Aug 29, 2005 3:56 am
by Manarius
I have no idea why the repair manual would tell you to remove the e-brake cable for the front brakes. I know for a fact that the e-brake controls the rear brakes. I've never done the fronts on my car, but they couldn't be any different from the back. Brakes on my car are a sinch. One bolt and I can remove the pads and place the new ones back in. It's a hell of a lot easier then the ones on my other cars. Thank God Subaru made it easy.

I will admit though, my car has more stopping power then my '97 Camry (But it's disc-drum), but it pales in comparison to my '03 Grand Prix (that thing stops fast and hard).

Posted: Mon Aug 29, 2005 4:55 am
by Legacypusher
Of course I know that the parking brake cable goes to the rear brakes, I was just pointing out the silliness of the old Chilton's book. I really, really, would love to see a photo of your "plate on a screw," though. It might be a great tool for a lot of us. Thanks for replying, and for the info.

Posted: Mon Aug 29, 2005 7:40 am
by scottzg
If theres some screw that you can bend, mine is hosed and i have incredible thumb power. I always push the piston back in with my hands.

Posted: Mon Aug 29, 2005 2:47 pm
by professor
that passage applies to brakes that have the e-brake actuator connected to the piston

basically on that type of set-up, then you pull the e-brake, it rotates an arm mechanically attached to the back of the piston, moving it forward on the screw and engaging the brake mechanically, through the disc pads

our Legacy's do not have this so no worries.

the rears on many Hondas do have this. And trying to push the caliper straight in does not work, but it would be pretty hard to damage it. It just doesn't move. the piston face has a X-shaped indentation which fits a special tool that goes on a ratchet. I use a lawnmower blade as a giant screwdriver, which works well.

this type of systrem sucks, it tends to warp rotors and leave residue as your pad sorta melts onto the rotor a bit if you stop with hot brakes, and engage the e-brake

Posted: Mon Aug 29, 2005 4:26 pm
by vrg3
"Plate on a screw:"

http://www.tooldesk.com/products/produc ... spx+id+189

A c-clamp and one of your old pads will indeed work just fine though.

But, yeah, that passage in the Chilton's manual isn't about our cars.

Posted: Mon Aug 29, 2005 6:08 pm
by Busdriver
The rubber boot over the guide was almost gone on the side with the bigger pads (less worn). So can you slide the caliper off the guide after loosening the bolt, so I can leave the other assembly on the car? I'll try to pick up a new boot for this if possible....
Thanks for your replies and welcomes!!

Posted: Mon Aug 29, 2005 6:27 pm
by vrg3
Yes, you can slide the caliper off the guide pin after removing the lock pin, leaving the bracket on the car.

Posted: Tue Aug 30, 2005 5:25 am
by Legacypusher
Neat. I was wondering what the"plate on a screw" looked like. I had visions of other things. Thanks for the photo.

Posted: Tue Aug 30, 2005 2:44 pm
by Manarius
vrg3 wrote:"Plate on a screw:"

http://www.tooldesk.com/products/produc ... spx+id+189

A c-clamp and one of your old pads will indeed work just fine though.

But, yeah, that passage in the Chilton's manual isn't about our cars.
Well, there it is. Nifty tool ain't it :P