Quick brakes issue

[andreigbs]

Hi folks,

In the process of changing out my rear brakes last night, I ran into a couple problems.

(1) The LR pads were about at 60% life left
(2) The RR pads were worn down to the linings and a little beyond

So I replaced everything, lubed the slider pins and proceeded to do a little bleeding.

First tried the pedal pumping 2 person method: no fluid came out of the LR caliper. Strange, so I hooked up the Motive Power Bleeder. As soon as I had a few PSI fluid started to flow.

Also, brake pedal goes to floor with a couple "notchy" points in travel and comes back up by itself.

I'm going to go back today and bleed all 4 corners, clutch and ABS pump using the Motive Bleeder and hope this cures it.

But why would the pedal not push out fluid on the LR while the Motive does?

 

[andreigbs]

Anyone? Anyone? Bueller?

 

[Powder Hound]

Sounds like some kind of blockage or corrosion either at the caliper or possibly in the ABS pump. But it is really hard to say. Did the pedal ever feel soft before? And did both parking brake cables work OK?

Was there any rust or corrosion on the left rotor? Wear/heavy use indication?

 

[andreigbs]

I'll be checking for any blockage just now, will continue to flush using Motive Bleeder and will check back.

The pedal was normal as long as I remember driving the car (the last 3.5 years) but after this brake job, I noticed the LR pads are not worn like the RR pads. And now this soft pedal business. Must be air in the system somewhere, hope it's NOT the MC. Keep giving me ideas, guys. I'm working through the problem.

 

[andreigbs]

Ok, I've bled the ABS pump about 10 times and also pressure bled all 4 corners and gone through about half a gallon of brake fluid.

I noticed a bunch of small particles in the flow of fluid especially at the rear. After doing this, the pedal started to get stiffer. I started up the engine and let the power assist working on the brakes, they got progressively harder and smoother at the same time.

Went for a drive and brakes work great, pedal stopping about halfway down as before.

The only problem now is that the RR wheel is burning hot! All other wheels are about the same temps.I'm guessing I'll need to unbolt everything off and re-lube the slider pins some more. This is the same side that wore thru its pads much faster.

Any other ideas on why one side consistently sticks and wears out faster?

 

[NB_TDi]

Did you remove the bleeder screws and ensure they were clear of any gunk?

 

[sdk131]

Did you loosen the parking brake cable in the center console after installing the new pads? I had the same problem as you after installing new pads, and loosening the cable fixed it.

 

[Ausgezeichnet TDi]

Did you remove the bleeder screws and ensure they were clear of any gunk?

+1, you need to see that the bleeders aren't rusted and are clear of crap. When rotating the rear caliper pistons back into the bore, did you open the bleeder screw? Not opening the bleeder screw when you push that piston back in allows nasty fluid to push back up to the ABS unit (no bueno). How easily did the rear caliper pistons move when you re-seated them? Shouldn't have to gorilla those back into place....what kind of caliper lube are you using? Do not use Anti-seize! No matter what tech tells you to use anti-seize, I've seen time and time again caliper slides sticking because guys slapped on gobs of anti-seize on the pins and landings. They sell caliper lube either Permatex Green Synthetic or Syl-Glide, both get the job done right.

EDIT: Don't rule out your brake hoses either, over time they deteriorate internally and can cause a goofy pedal.

 

[andreigbs]

NB: I checked all bleeder screws for crap and corrosion, none found. There was some particles flowing out while bleeding, however, along with small bubbles of air. Got all that out, all nice and new fluid now.

sdk: I saw the procedure in the Bentley and it looks quite a cumbersome task to remove the center console. I'm sure I should at least check the adjustment on the parking brake. Will do that this weekend hopefully.

Ausgezeichnet: That was one of my mistakes; NOT opening the bleeder screws when turning the pistons back in. I did the ABS pump bleed procedure with VCDS last night about 15 cycles and things improved drastically. Especially pedal feel, like progressive and smooth yet firm. The pedal feels great now.

I used caliper grease only, no antiseize, and only on the slider pins. I cleaned everything well with brake parts cleaner, including the ABS sensor and ring on the inside of the hub, then cleaned the front ones just for good measure.

The only issues now are that the RR caliper is sticking. I can feel it drag when coming to a stop where you can usually roll forward/backward. It won't budge unless it's quite a steep hill. On flat road, it will stop itself from about 5 mph. Also, when touching the wheel it's very hot compared to the LR. This is most likely a long-standing issue, since the previous set of pads got used up so fast because it was dragging. It wasn't obvious before, like no extra heat anything. Now it's obvious.

Besides checking and adjust parking brake, what else can I do to free up the caliper that's dragging? What's the most common fix that I may be overlooking?

Thanks for the ideas guys, I appreciate your input.

 

[Ausgezeichnet TDi]

andreigbs, how easy were the calipers to retract? Was the RR harder than the left? How much fluid flow is there out of the bleeder in the left compared to the right? If you have more flow in the left, you may have a clogged brake hose on the right. **This test is best done with the vehicle running**Did you use a wire brush and brush the pad landings, as well as the metal plates that the pad ends slide on? It is a good idea to put a tiny amount of caliper lube on those parts to ease braking. If you put too much on, it catches all the brake dust and water from the road.

Calipers seize, and get stuck from time to time. In most cases they seize completely. The part that retracts the piston after the brakes are applied, is the piston seal. It doesn't move much, but its enough so that there is an air gap between the rotor and pads. If this is gummed up or just worn, it seizes. Also, water in brake fluid. Brake fluid is hygroscopic meaning that it absorbs moisture from the air. That is why brakes need to be flushed every other year to prevent rust and buildup in the system.

You most likely have a stuck caliper, but double check your fluid pressures and parking brake adjustment to make sure....brakes are a headache aren't they?

 

[sootie pipe]

Sounds like some kind of blockage or corrosion either at the caliper or possibly in the ABS pump. But it is really hard to say. Did the pedal ever feel soft before? And did both parking brake cables work OK?

Was there any rust or corrosion on the left rotor? Wear/heavy use indication?

abs would not even be active during bleeding without a vagcom or 5052. what would rust on the rotor have to do with bleeding?

 

[jetta 97]

Ok, I've bled the ABS pump about 10 times and also pressure bled all 4 corners and gone through about half a gallon of brake fluid.

I noticed a bunch of small particles in the flow of fluid especially at the rear. After doing this, the pedal started to get stiffer. I started up the engine and let the power assist working on the brakes, they got progressively harder and smoother at the same time.

Went for a drive and brakes work great, pedal stopping about halfway down as before.

The only problem now is that the RR wheel is burning hot! All other wheels are about the same temps.I'm guessing I'll need to unbolt everything off and re-lube the slider pins some more. This is the same side that wore thru its pads much faster.

Any other ideas on why one side consistently sticks and wears out faster?

You have problem with RR caliper or hose. It is getting stock in side or hose is has no flow,and that why you had RR pad was all gone and LR was OK.
You need to this:
Take out RR hose and see can you blow through it easy. If you can you have problem with caliper and it will need new caliper.

 

[andreigbs]

Excellent ideas guys, this is exactly what I needed.

Ausgezeichnet: I disconnected BOTH lines at the rear earlier in the process of bleeding the lines because I couldn't get ANY fluid out by the 2-man pump method. I thought there may be blockage, so I disconnected the lines and saw no obstruction in the flow. When applying positive pressure with the Motive bleeder, fluid flow right out on BOTH sides. The pedal, however, wasn't doing the same thing. I remember both calipers to be a little hard to push the piston back in. Sometimes they would bind for just a bit then become easy to turn, get harder again, then easy to turn. Significance? As for fluid, it's all been bled out and replaced with new DOT4 stuff. Including the ABS pump, and the last time I did it was 2 years ago so I doubt there was moisture in the fluid.

jetta97: I'm leaning on that possible scenario myself. Friday I took the RR apart again, pushed the piston back in after cleaning it and all around it with a brush (then went and did the same on the LR) and lubed up the piston slightly around its circumference before putting things back together.

Today after driving around about 60 miles on the freeway and around town, I noticed that the brakes don't drag much anymore. Even on flat, level road the car will keep rolling ever so slightly. If there is even a slight incline it will roll that direction if the brakes are released. I take that to be a good sign, however, at times (3/10 times) it feels like they may be dragging slightly. After coming home I tried the heat test again and this time all the wheels felt the same temp. So the dragging has been reduced drastically.

I guess I'll keep an eye on the rear brakes and check how evenly they wear. If the trend continues (the RR wearing out before the LR) I'll swap the pads from left to right and plan on purchasing new calipers. Probably the safe thing to do anyway, but funds are a little tight ATM.

Oh, I checked the parking brake adjustment as well and both cables are adjusted correctly. There is a 2mm gap between the stop and the cable end, like the Bentley says there should be. I think it's mainly a caliper issue now. When I do change them out, I'll also replace the rubber hoses in the rear for good measure.

Thanks for the advice folks, this is what makes TDIclub priceless.

 

[jetta 97]

Good job. I thing you should be OK now as they not getting hot.
Thank you for posting results after repair .Some one may need in future.

 

[andreigbs]

Yes, I'm glad it wasn't something serious like the MC or worse. I'll keep an eye on it, but for now things are normal.

And i too hate it when people post a problem and later fix it after many suggestions provided, but they never come back to say," hey, this worked and i'm back on the road now, thanks!"

This is why i'm hooked on this site...