Brake problem

Post by **Petros** » Thu Sep 06, 2007 10:36 pm

I rarely get my wheels to lock on dry pavement.

A bummer on the reman MCs. I am surprised to read about all of your trouble, I have not had such experience with any brakes, Toyota or otherwise.

If I intend to keep my car I have sworn off remans. Too much bad luck, one example was a reman water pump for my wife's MPV 4wd minivan: it cost me a radiator, and to have to back flush the heater core, when it shredded up itself (sending metal chips all over the cooling system) and nearly cost me a damaged engine. It was another 7 hour R and R for a new water pump (major job on that car). Buying new only costs a bit more from NAPA or Autozone.

I will have to do my brakes soon too, my pads are worn and at least one of my disks is warped. But fortunately my MC appears good. I think I would buy the kit and rebuild it myself if I could not buy a new MC.

About a year ago my mc went out (badly), and being sunday afternoon I needed my car for monday. I needed a fix fast, I happen to have an extra MC off my parts car, I disassembled both MCs and cleaned all of the parts with brake parts cleaner. I used 800 grit sandpaper (wet) in the best bore, and mixed and matched all of the best parts together to make one good one. I installed and bled it no problem. It has worked perfectly ever since and I have no plans to replace it yet.

I think rebuilding an MC is pretty easy (I have done it many times in the last 30 years). It is hard to imagine they screwed up that many (must be using idiot labor somewhere far away).

If all else fails you might see about ordering a rebuild kit for your old MC (or one from a wrecking yard), I am fairly certain that Autozone can get them. I have found that even if you can not get the bore perfect (i.e. get all of the pits out), they will still work well. In fact if the pitting is deep, if you hone to remove it all, the bore will be too big dia. Perhaps the trick is to simply hone untill smooth, not until clean or you end up with what you got. A bad rebuild.

I might upgrade to the vented disks, though I am not sure I want to mess around with shimming the disk to center it on the wider calipers. I think the brakes are too flimsly for this car, which is much heavier than the Tercel sedan the brakes come from. Toyota should have known better. Oh well.

takza · Post by **takza** » Fri Sep 07, 2007 4:54 am

keith wrote:I did get it to stop in 150' from 60 mph, but I couldn't get the brakes to lock even the slightest.

With the 14" 60 Kumhos and doughnuts all around...mine won't lock on dry pavement...but you wouldn't want to follow too close if I decide to stop. I do have some flexline flex under hard braking...need those braided lines if I'm going to race.

keith · Post by **keith** » Fri Sep 07, 2007 6:23 pm

Petros,

If you go to vented discs and use the matching calipers, why do you have to shim? I was following the posts on upgrading the brakes and I don't remember anything about shims.

I used to rebuild MC's when they weren't so easy, back in the days of single cylinder MC's. You had to assemble everything on those. I stopped after doing my first dual MC. It was easier but the kit cost about the same as a reman, so I've gone that route instead.

takza, maybe with Kumho's, I'd be less concerned, but with 185/65-14 Dunlop SP40's, that's a different story.

Post by **Petros** » Mon Sep 10, 2007 6:31 pm

I have not tried it yet, but I understand to install the vented disks you have to shim the disk out to get it centered on the thicker caliper (because of the thicker disk).

It might be possible to shave the pads so it will bolt up without the disk centered on the caliper. It should still work fine, you just will not get as many miles out of the pads. There was a thread on this topic and someone who did the conversion noted the need for the shim to center the disk. I do not think it is a strait bolt-on conversion.

If it will simply bolt-up I would like to know, I will order all the parts I need right now and put them on this week-end.

keith · Post by **keith** » Tue Sep 11, 2007 6:21 pm

I'll have to go back and read all the posts on this, I don't remember anything about shims. Maybe I just overlooked it. I would not use shims, too much risk in getting the rotor to shimmy and that would cause more problems.

Booster came in today. By the time I got home from work, I only had 15 min to work on it, so all I've done is disconnect the pedal and light switch.

keith · Post by **keith** » Sat Sep 15, 2007 11:55 am

Well that was a waste of money, the new booster hasn't improved anything. I did get the passenger side front wheel to lock again, it wasn't even doing that before, but the brakes still don't feel good. There is too much pedal travel and too much force required for a normal stop. It feels like the rotors have been greased, but the thing really nose dives when the brakes are applied.

It does have new shocks and struts all around.

I did the vacuum bleed again using the brake grease around the base of the bleeders. It worked better this time. I don't think there is any air in the system because you can't "pump up" the brakes.

CASE · Post by **CASE** » Sun Sep 16, 2007 2:11 am

Perhaps your back brakes are grabbing more than they should?-It can be really frustrating replacing everything from the MC down to the disk, only to find you needed something stupid like a bleeder valve. I don't race or rally, but for normal roadtripping, I've had good experience with OE MasterCyls off the wrecker, there's alot of new cars crashed these days, and many standard Toyota parts are far superior to remanufractures, even with miles on'em- Besides, a my old tercel with few upgrades handles really well in a frontWD dirt slide, even weighed down. If you can still steer well in a slide, maybe the grabbing isn't that much of a prob? Have you tried tying a canoe on top?, maybe it lends stability-huhhuh

I did the vacuum bleed again using the brake grease around the base of the bleeders. It worked better this time. I don't think there is any air in the system because you can't "pump up" the brakes.[/quote]

takza · Post by **takza** » Sun Sep 16, 2007 3:55 am

I'm not sure how the T4WD is rated...but I noticed yesterday a small 2400 lb car that stopped 60-0 in 150 ft.

I think you'd need braided ss lines front and back to get rid of the extra pedal play under hard braking?

http://www.edmunds.com/ownership/drivin ... ticle.html

http://autos.aol.com/article/power/v2/_ ... 1109990001

Testing a stock '96 Mazda Miata (sports car?)

"We found our average 60-0 mph stopping distance to be 187.98 feet. This is a greater distance than the standards set by professional drivers, but remember the test environment -- just like that which you'd find on the street, everyday. This is what you'd do. The factory pads and rotors performed admirably and didn't heat up excessively during our test run, but they transmitted limited feel when pushed hard and locked up the tires too easily."

"Not surprising, the slotted Moss Motors rotors and hi-po Hawk pads combined to deliver the quickest stops of our testing day. The 60 to 0 stops in our Mazda Miata test car averaged out to 157.94 feet. That's about 30 feet shorter than with stock equipment, and 10 feet shorter than with just upgraded pads."

So at 150'...what's not to like?

If you are getting nose dive with new springs and struts all around...the next step is the DOUGHNUT? When you lose most of the stopping power from the rear drums and most braking is from the front tires....they have to be slipping some? My front struts are marginal...but I don't seen any real nosedive with 2 DNs up front each side.

keith · Post by **keith** » Sun Sep 16, 2007 9:11 am

Everything is relative. I do my testing in front of my house. I live out in the country so there is little traffic and my nearest neighbor is almost a 1/4 mile away. The road is good. I am not including reaction or perception time and although I don't have sophisticated test equipment so there is some variation between tests. I have five vehicles in the yard.

I have not tested my son's Spec-V, but I suspect it would stop the quickest. How ever, my 97 Nissan truck stops in about 130' with the Michelins, 150' with the Firestones that came on it. Note the Firestones actually improved with age, but when they were new, they were very slippery. The Saturn stops easily in 130' and my wife's Honda has stopped in as little as 120', but now takes about 130' as well. The road may have been a little better when I did that stop in 120, or maybe I was going slightly less than 60, or hit the brakes a little early.

My property is 150' wide and as a tree line in each side as well as a clearly visible post.

But most important to me is the feel, they just don't feel right. I may look into getting some Brembo slotted rotors and either the Hawk or EBC pads, but I really want to solve the problem with the feel first.

takza · Post by **takza** » Sun Sep 16, 2007 6:32 pm

I never tested them...but I swear the Tercel would stop faster than my old 300ZX...even with new brakes all around....it was 1000 lbs heavier.

keith · Post by **keith** » Sat Sep 22, 2007 10:55 am

I went to cartalk.com and posted my problem there. It turned into one of the most active postings currently.

http://action.publicbroadcasting.net/ca ... /list.page

One suggestion was to check the brakes on a gravel road. I have a dirt road across the street from me so I tried it there. At 20-25 mph, both front wheels would lock, but not the rears. Well the RR locked for about a foot on one stop, but not on the other 3-4 attempts.

What I didn't expect was that from 20-25 mph, the car stopped in about one car length, go figure.

Anyone got a spare metering valve? They run about $200 from the dealer. Ouch!

takza · Post by **takza** » Sun Sep 23, 2007 2:03 am

If you are using the bottle method to bleed brakes...you are pulling air back in when you let the pedal up? Using vacuum this doesn't happen...and grease on the bleeder threads helps.

I swear I had about the same kind of thing or similar until I vac bleed the system.

I also drove an Escort with no vac booster for awhile...took some serious leg power to get it to stop.

They probably proportion front and rear so there is little chance that the rears will lock even on gravel....maybe some real good shoes on the back?

But you've got some serious mechanics on your case over there.

keith · Post by **keith** » Sun Sep 23, 2007 7:37 am

The way I do the bottle bleed keeps air from being sucked back in. Because the hose goes uphill from the bleed valve, the air bubbles travel up leaving fluid only in the tube at the bleeder.

I did do the vac bleed with grease around the fitting bleed valves. It worked with the grease. I pulled enough brake fluid to fill the cup twice on each side and didn't get any air bubbles.

I think it is time to put new shoes on the rear, there must be something wrong with the friction material. The question is, do I take them back to Autozone where I can get free replacements or do I go with what might be better, and what is better? I'm also thinking of new pads on the front again, either EBC or Hawk. I'm leaning towards Hawk right now.

I have a Saturn with disk front and drum rear. I took it out on the dirt road and checked, it locked up all 4 on the dirt.

I may have been incorrect on the stopping distance too. I was using the length of the "skid" mark to judge the stopping distance. The Saturn took about 2.5 car lengths to stop from 20 mph. On that test, I used markers instead of the "skid" mark. It looks like the Tercel doesn't lock up as quickly.

Typrus · Post by **Typrus** » Sun Sep 23, 2007 8:17 am

I can lock all 4 on dry pave when I try for it. Well, before I changed drums. I have a feeling one of them isn't set just right, but I don't want to toy with it. Do ours adjust with e-brake, braking backwards, or some other method?
How are your drums? Make sure they aren't over limit. Both mine were .040 over, easy. It was bad >.< Bought new NAPA ones (looked beautiful) and painted them with 1400 degree flat-black block/exhaust paint. Then I cured them on the grill at 400 degrees for 2 hours. Put a lovely blue surface-coat on them everywhere I didn't put my fingers. Heh. Probably just the propane. Paint looks real nice and it set up real tough. 3 layers.

Find out if it really is the combination valve. If it is, I have one off of blue.

keith · Post by **keith** » Sun Sep 23, 2007 6:04 pm

Well I'm not sure, at least not 100% sure. Today I pulled the rear wheels and drums, cleaned everything again, greases the backing plates and sanded the shoes and inside of the drums. Put it all back together and hit the road again. No change.

I did a 60-0 test again. I missed the 60 slightly, hit the brakes at 58 as I passed the corner of my property. I got a small lockup of the Rf wheel about half way thru the stop but it stopped in about 135 feet.

Then I decided to compare it to the Saturn, which I feel has excellent brakes. I hit the corner at 60, the brakes grabbed quickly but kept locking, so I had to pump them. It took 140 feet to stop.

Both cars weight 2450 lbs =/-, both have the same size tires, 185/65-14. The Tercel has new Dunlop SP40's, the Saturn has half worn Bridgestone Turanza's.

I put EBC slotted rotors and EBC Ultimax pads on the Saturn. They don't make rotors for the Tercel but I guess I could try the Ultimax pads.