78 Westy Bus Swerving Left Under Braking

[vwlover77]

Moderate to hard stops pull to the left, and require dialing in a lot of steering to the right to get a straight stop.

I pulled the front wheels and inspected the brakes:

- Plenty of pad material on all 4 pads and the rotors look great.
- Pad thickness seemed uniform all around.
- No grease or brake fluid anywhere it shouldn't be.
- Pushed pads and pistons back into the calipers with no problem.
- Rubber bellows on the pistons looked intact (as best I could tell without pulling the pads)
- Pistons and pads came right back out when I pumped the brake pedal a few times.

I pressed and held the brake pedal down hard for a few seconds, then quickly got to the rotor and turned it to see if the caliper was hanging up.
I noticed that the passenger side was maintaining some pressure on the pads for 10 seconds or so after I started turning it. It could still be turned by hand, but the driver's side would almost spin freely as soon as the pedal was released.

Does this sound like the beginnings of issues with the rubber hoses? I'm wondering if I should start by replacing them first. I do not know their history... could even be original!!!

Thoughts?

[covelo]

Mine does this too. Almost the exact same symptoms. The only difference is that mine seems to veer left worst when I apply moderate brake pressure, but straightens out when I brake harder. Almost like the right front brake is catching up.

Would be very interested in what people find. I'm so used to this that I now correct automatically and almost veer to the right in our Prius after driving the bus for a day.

[Amskeptic]

Don, if you can verify that all four pistons glided back in their bores with equal effortlessness, then yes, it may be a hose coming apart internally.
Next time you go out and drive, see if the right front hubcap is warmer than the left after some mixed surface street driving with plenty of moderately hard stops. Also, check the rear brakes both for adjustment and release drag.
Colin

[glasseye]

Just went though this with the Asstro back in November. New hoses left and right cured the problem immediately.

[Bookwus]

Hiya Don,

As you probably well know, those rubber brake hoses are sneaky little.......well, they can hide a problem.

Here's a picture of samples taken from the brake hoses at each corner of a Bug.............



....and you can see that the internal diameters are all different (due to swelling) but the external diameters are all the same. They look great on the outside while they are failing on the inside.

[vwlover77]

Wow... That photo tells a story, for sure! Well, I'll start with the hoses because it's a low-cost way to begin, and it should probably be done anyway. I'll post back here afterward and give a full report!

Colin, I did check wheel temps after some driving yesterday - no significant heat at any wheel. The rear brakes were last adjusted by you during our visit at Sean G's. I've only logged a few thousand miles since then so I think they should be fine.

Thanks!

[Randy in Maine]

I am going to switch mine to the stainless ones from aircooled. $100 does them all...

http://www.aircooled.net/new-bin/viewpr ... 01&cartid=

[vwlover77]

I just got my new front brake hoses. Stupid question: The hose does not swivel in the fittings at either end. I'm assuming that neither the caliper or the steel line have swivel fittings. So how do I put them on without twisting the rubber hose?

[Ritter]

The steel lines have swivel fittings (or some such thingy) at both ends (it will be obvious when you start the disconnect). Use brake line wrenches or you'll strip the fitting in short order. Use care on the steel line from the rubber to caliper. I broke mine. German Supply has them pre bent.

[Amskeptic]

I just got my new front brake hoses. Stupid question: The hose does not swivel in the fittings at either end. I'm assuming that neither the caliper or the steel line have swivel fittings. So how do I put them on without twisting the rubber hose?

The nuts on the metal lines spin around the metal. The flare of the metal line will give you your seal. As you install the rubber lines, make sure to keep hose straight throughout its length. Usually they have stripes that will provide you reference.
Colin

[vwlover77]

The new front hoses are installed. There is some slight improvement, but still not a straight stop under hard braking.

I'm now suspecting something in the rear, especially after the left rear locked up briefly during a pretty hard stop on my test drive.

I'll check the rear adjustment and make sure the wheel cylinder is not sticky. I should replace the rear hoses too as it appeared that the front were indeed the originals.

Stay tuned for further updates!

[Amskeptic]

I'll check the rear adjustment and make sure the wheel cylinder is not sicky. I should replace the rear hoses too as it appeared that the front were indeed the originals.

Told ya told ya

Also, check the rear brakes both for adjustment and release drag.

so let me crow. . . . . caw.
OK, rear drum brakes that prematurely lock often have issues with glaze on the drums. The glaze is sometimes just from enormous build-up of dust if they have not been touched in some time, but many times it is from a slightly leaky wheel cylinder. If you do not have damp wheel cylinder boots (when you peel them back to inspect), I would definitely sand the drum with our ol' cross-hatch pattern, and lightly scuff the linings too while you are there. Before you touch the linings, however, compare the actual contact surface with the right brake's linings. Any difference? Rear brakes are more susceptible to variances due to emergency brake adjustments or sticking cables or driving around the the ebrake still applied. You want to mirror every operation on both sides of the car.

I do not know why my original brake hoses are defying the laws of physics. I have only done one brake flush since I have owned the car, and that was at Bob D's house with his cool pressure bleeder and blue brake fluid. The hoses are still fine. I do not understand.
Colin

[vwlover77]

Between last night and this afternoon, I have now had both rear drums off the Bus. The adjustment on both seemed fine and neither had a sticky or wet wheel cylinder.

The lower portion of one of the shoes on the passenger side looks like it is not making any contact with the drum. I thought this might explain why I'm getting more braking on the driver's side (pulling left), but when I looked at that side, I found even larger portions of both shoes that apparently are not touching the drum.

I dutifully sanded the drums with a 45 degree crosshatch and also gave the linings a light sanding.

I only completed the passenger side last night and noticed no difference in the braking today. I can't comment on the results of the driver's side as I haven't driven it since. I also bled the right front caliper again to make sure I had no air in it reducing its braking force. There did not appear to be any. (By the way, I only need to use the upper bleeder valve, right?)

[Amskeptic]

Between last night and this afternoon, I have now had both rear drums off the Bus. The adjustment on both seemed fine and neither had a sticky or wet wheel cylinder.

The lower portion of one of the shoes on the passenger side looks like it is not making any contact with the drum. I thought this might explain why I'm getting more braking on the driver's side (pulling left), but when I looked at that side, I found even larger portions of both shoes that apparently are not touching the drum.

I dutifully sanded the drums with a 45 degree crosshatch and also gave the linings a light sanding.

I only completed the passenger side last night and noticed no difference in the braking today. I can't comment on the results of the driver's side as I haven't driven it since. I also bled the right front caliper again to make sure I had no air in it reducing its braking force. There did not appear to be any. (By the way, I only need to use the upper bleeder valve, right?)

My last option would be to switch first the front brake pads left to right
(left outer to right inner left inner to right outer and vice versa) and check for swerving, then do the same for the rears if there was no change..

I would ONLY do this if my curiosity was inflamed (which mine is now) with trying to find the real real reason for this bad behavior. Tire pressures good. How about tread wear on the tires? Any anomalies? Fascinating from the armchair here.
Get to work.
Colin

PS, air does not reduce force, it merely makes the pedal less efficient.

[vwlover77]

I'm beginning to think the passenger side rear wheel cylinder is gummed up or stuck. I adjusted the rear brakes again last night and purposely adjusted the passenger side so both shoes were rubbing ever so slightly on the drum.

I drove it around town today at lunch to pick up AC parts for the wife's car and when I parked it, the driver's side drum was quite warm to the touch, while the passenger side was cold.

Thoughts?