PDA

View Full Version : Brakes feel a bit odd after getting the car back on the road.



Nitro_Alltrac
01-02-2017, 08:45 PM
As I mention previously, the brakes felt soft after I got the All Trac back on the road. I got them bled over the past couple of days and got to take it for a drive today.

They still feel strange. Now the pedal initially feels about right at the start of application but then drops about an inch and then gets a little firmer but not what it should be. It's hard to accurately describe but the gist of it is that the pedal is still soft and the brakes not stopping like they should. Hit the brakes hard and it pulls to the right. Hit the brakes really hard and the right front only locks up.

The front rotors are both now shiny after bleeding, the rears still have a sheen of surface rust on them. Nothing bad but they are not shiny like they should be. The rears don't look like they are operating fully.

I'm not sure where to go next. I think the calipers are OK. All four appear to be working, at least to some extent. It looks like the front brakes are working better than the rears right now.

I was thinking for a while that maybe it's something to do with the master cylinder or the booster but given how the Toyota dual circuit system works, diagonal instead of front and back, I'm thinking that's probably not the case. Proportioning valve maybe going bad?

The car does have ABS which has never worked in the ten plus years I've had the car. I guess there could be an issue in the brick or something but I don't really think so.

Any suggestions?

ChrisD
01-02-2017, 09:12 PM
Most common thing that I've seen is the pistons seizing in there. It's possible. Can you see the pads moving when the brakes are applied? I'd start there and start working backwards from there.

celica91gts
01-02-2017, 09:55 PM
check your brake lines?

Nitro_Alltrac
01-02-2017, 11:52 PM
No leak in the lines. I've got fluid at all four calipers and the master cylinder is where it should be.

Chris, I'll double check but I think the pistons are moving. I've got evidence in the rear that pads are hitting the rotors when the pedal is pressed but I'll double check. I've got a set of used calipers that I got from AllTracMan of few years ago. I can swap those in if the weather will cooperate.

Shadowlife25
01-03-2017, 12:07 AM
No leak in the lines. I've got fluid at all four calipers and the master cylinder is where it should be.

Chris, I'll double check but I think the pistons are moving. I've got evidence in the rear that pads are hitting the rotors when the pedal is pressed but I'll double check. I've got a set of used calipers that I got from AllTracMan of few years ago. I can swap those in if the weather will cooperate.

If you are going to go to the trouble of installing another set of calipers, just rebuild them before hand. The O rings and seals and pins are inexpensive and it only takes a few minutes per side to do.

MrWOT
01-10-2017, 06:38 PM
If the pedal drops, I would think the master cylinder. If it's spongy, change the fluid out. Go find some 5.1 to swap into it. Offset pad wear will indicate a sticking caliper (inside vs. outside).

Nitro_Alltrac
01-15-2017, 08:50 PM
Had a chance to clean the guide pins on the rear. Both of those rotors were only showing minimal sweep from the pads. The pins were sticking, especially the one on the right rear. Like never go the caliper off.

I cleaned those up and lubed them really good and got them moving smoothly. I also rebled the rear brakes.

While better, it's still not right. The pedal starts out firmer and initially goes to where it normal would start to take up good, hesitates for a second and then goes down further. It doesn't go to the floor or anything but it goes down a lot further that it should. The car will stop but nothing like it should. It's always had excellent brakes.

Both front rotors and the left rear show a good pad sweep pattern so those calipers appear to be working OK now. The right rear is only show sweep about an inch wide the middle of the rotor. I'm thinking that in addition to what ever else is going on that the right rear caliper is going to need to be replaced.

I'm leaning toward the master cylinder going bad as the main issue. Everything I've done has helped but it's not where it needs to be yet.

Opinions and suggestions?

MrWOT
01-20-2017, 05:36 PM
Master. From how you describe the pedal dropping.

Nitro_Alltrac
01-21-2017, 02:16 PM
I will hopefully find out today.

I picked up an new Aisin replacement master cylinder. Weather is supposed to be good today.

Nitro_Alltrac
01-21-2017, 09:12 PM
Got the master cylinder on. I didn't get a chance to drive it other than back and forth in the driveway but once again it feels like it helped but the brakes still don't feel like they should.

I will have to get it out on the street and actually drive it to make a 100% sure on the assessment. The pedal feels better just not where it should be I think.

I've got to check to see if there is some kind of special bleeding process where it has the ABS system on it. I'm using my MityVac hand pump to bleed them. The left rear caliper seemed to have a lot of air come out of that line. The others not so much. They probably to need to bled some more.

And on top of this, I noticed that I have something dripping on the rear subframe on the left side. It's right about where the left front mount is on the subframe. I think it's fuel. After I noticed it I started the car, no leak while running but after shutting it off I had drips. Nothing big but it was dripping some.

I think I'm going to take it in to a shop I use and have them go through the brakes and check that leak. Probably some of the hardline replaced. With it being winter and not having a garage, my repair ability this time of year is severely limited. And I don't want to leave it sitting longer. The longer it sits, the more crap happens. I just want to start driving it again. If that can't happen soon, I'm going to have to reevaluate my plans. :sad2::sad2:

Nitro_Alltrac
02-08-2017, 09:39 PM
Got the car back from the shop yesterday. They replace most of the rear brake hard lines. They were just starting to seep. I guess that's why I wasn't finding the leak. I've got brakes now.

Took it for a quick spin after hooking up the ground wire for the my oil pressure gauge and putting the vacuum line back on the MAP sensor. Needs to say, it ran like shit last night but I knew right away they had left some stuff loose.

Any way, brakes are back to where they need to be now. I've got to get some new wiper blades and I'll start driving him to work again. The blades on there now are like wiping the windshield with a mud squeegee.

It's running fairly good. I've got an ignition stumble under load that I'm going to have to try to track down. It's worst under acceleration from a stop going u through the gears. When you accelerate at cruising speed it seems fine. It's not bucking or any thing, it's just a stumble you can feel.

Hopefully everything continues to work like it should. I'll have to make my decision after I drive it for a bit if I'm going to drop the cash for the engine swap.

But for the moment, he's back on the road.

The wife called him Little Red last night. I kind of like that.

ChrisD
02-16-2017, 01:58 PM
That's good to hear. Yeah with the rust issues you saw, it's pretty common the brake lines would follow suit. Mine did also, did a repair on them a few years ago. Another friend of mine just finished redoing his as well.

As for stumbling. Darn. Well check the usual culprits, ignition cap / rotor / plugs. Then wires potentially. What plugs? Maybe they just got fouled. If they are coppers that's possible. I only really run coppers on my 165, the 205 I've always done Iridiums for longevity.