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Wed Aug 20, 2014 5:54 am

I have noticed that the bus pulls to the right a little and when I brake, it oulls to the right quite noticeably. I bled the brakes, the hoses were changed, purged the old brake fluid. What could it be?

Bad Caliper (right...OR LEFT)

I looked up prices for calipers......over 200 for one caliper!?!?!!? ATE of course.

These calipers aren't that old < 5 years old

Wed Aug 20, 2014 6:18 am

The bus turns away from bad or weak caliper- and you need 2 if you just buy 1 the bus will pull towards the best caliper.

lots of material here on re building-

Wed Aug 20, 2014 6:53 am

If it pulls hard to the right, that means the right is braking/locking up harder/better than the left side. It might not be the left caliper is weak, especially that yours are fairly new I'd say. Maybe something on the right side is locking up/sticking. You'll have to inspect both sides for functionality and go from there.

Wed Aug 20, 2014 7:03 am

Yeah, I know back in the day the it was more cost effective to rebuild the calipers (if you knew what you were doing).

I guess were going back in time here.

So, intially I thought my caliper on the pasenger side was bad (dragging)

Wed Aug 20, 2014 7:06 am

I have looked at the wheels, the pads are good, rotor is fine. When I turn the rotor i hear the usual scraping noises

Wed Aug 20, 2014 7:07 am

quick test is jack it up and spin the wheels. :?:

What ever you do- you need to do it to both sides or :oops: :oops: :oops:

Wed Aug 20, 2014 7:31 am

That's what I did, I spun and heard the same sound of the rotor kinda scraping the brakes (which I read is normal)

Wed Aug 20, 2014 7:59 am

porschpow wrote: That's what I did, I spun and heard the same sound of the rotor kinda scraping the brakes (which I read is normal)

There are more things it could be than what have been listed.

Yes....it could be a caliper on the side opposite to the direction it pulls that is not generating enough clamping pressure. That can be caused by poor fluid flow from a swelled brake line, air in the caliper, or air in the hard line to that caliper. It generally will not be air in the forward master cylinder circuit or both calipers would have pressure issues.

However it could also have nothing to do with brake fluid pressure. It may be that the left side caliper cannot advance any further due to rust ridge or internal binding/swelling of the sealing ring.
Ray
It may also not be the fault of the opposite caliper. Its common with some pad brands that the density of the friction material changes as they wear down and you get to a harder layer.
If the rotors were ever rough and one side wore at a higher rate.....or if the inside or outside pad are wearing at a higher rate.....like because one side of the rotor was grooved from wear but the other was not.....you can reach a point where it will cause a caliper to have unbalanced criction pressure and it will cause pulling.

Also common is when a grease seal is leaking and putting grease on the inside of the rotor face. It may be causing slipping on your left side which will cause a pull to the right.

Also...if the pull is not a very hard one and if it seems intermittant or gets worse depending kn how much the steering wheel is turned....it can be a worn ball joint or tie rod end that causes this.

My advice is to not spend days piece mealing or discussion of one at a time possi ilities...which is why I wrote a longer post with more information......the simplest way is to simply jack up the front end, remove each wheel, pull the pads and inspect them for fluid or grease contamination, pull the calipers leaving them connected and inspect the seals, then check the rotors for warpage and play.....warpage in one rotor can cause pulling as it heats up......and then pull the rotor and check the inner seal for leakage and inner face for contamination.
This is about 20 minutes per side. If you have the rotor off....add another 20-30 minutes per side and about $6 per side and replace the seal and repack the bearings.

If your pads are not a top notch brand and they are worn to 1/2 or more...just replace them.

Do this...and when you have it back together...and if it still pulls....now you truely know what its NOT.

Personally I would just rebuild the calipers to be sure. Its dirt cheap and dead simple. You can get top notch kits from Rock auto for less than $20 per side. Ray

Wed Aug 20, 2014 10:18 am

You say that these calipers are 5 years old. I assume you are the person that replaced them? If so, are they good quality or crap? If you bought crappy quality calipers then I would suspect them. As Ray said rebuilding the calipers is really quite easy. I just shoot some shop air into the fitting and the pistons pop right out. Be careful or you can lose a finger. Place some wood between the pistons so when they pop they contact the soft wood. From there it's simple. Just clean and inspect the bore and piston. If all is good just remove and replace the square ring on each piston and install the new duct seals. There's no rocket science going on here.

Wed Aug 20, 2014 10:18 am

porschpow wrote: I have noticed that the bus pulls to the right a little and when I brake, it oulls to the right quite noticeably. I bled the brakes, the hoses were changed, purged the old brake fluid. What could it be?

Bad Caliper (right...OR LEFT)

I looked up prices for calipers......over 200 for one caliper!?!?!!? ATE of course.

These calipers aren't that old < 5 years old

If its pulling to the right as soon as you brake the issue lies in the left side. Most likely caliper issue.

Wed Aug 20, 2014 11:28 am

bus will pull towards the caliper that works the best. Or sometimes the rear can be doing it. Step on the brakes firmly about 5 MPH on a side street and then stop and see if either of the rears laid down rubber. I had a 1971 bay years ago where one of the rears was grabbing a little from leaking fluid and it was making appear if the fronts were pulling.

If it is the front you can feel it by spinning each one with someone lightly pressing on the brakes. The good one will bite sooner than the bad one.

I have seen issues where a broken or loose suspension can cause a vehicle to pull. All that said probably a 90% chance it is the left front that is sticking.

Wed Aug 20, 2014 11:32 am

Thanks a lot for all thr generous info.

I will first attack the back end of the bus adjust/clean the shoes (e-brake) THAN,

look a the front and see what is going on. They are ATE calipers IIRC, so they shouldn't be the cheapos.

Worst case worse, if I do need to rebuild it, i will hesitate because I will be unsure what to look out for (pitting, etc) than proceed to mess somethign up

Wed Aug 20, 2014 11:34 am

Things I did to the bus

tie rods were replaced recently
I greased the front end
new bearings were put in
rubber lines were replaced a few years ago
replaced the brake fluid then bled them

Wed Aug 20, 2014 11:38 am

i will hesitate because I will be unsure what to look out for (pitting, etc)

Like I said, it's not rocket science. Once the piston is removed you can easily run your finger inside the bore and outside the piston. It should be smooth. If it's pitted then replace the whole caliper. Note: The caliper is two halves bolted together. Do not take the halves apart from each other.

Wed Aug 20, 2014 8:07 pm

aeromech wrote: i will hesitate because I will be unsure what to look out for (pitting, etc)

Like I said, it's not rocket science. Once the piston is removed you can easily run your finger inside the bore and outside the piston. It should be smooth. If it's pitted then replace the whole caliper. Note: The caliper is two halves bolted together. Do not take the halves apart from each other.

This is true....but some things to add...about what works and doses not.

Caliper bores can have tons of rust pits and it will not be a problem....as long as its not just solid rust. If you can smooth it with wet dry sandpaper ....and what remains is shiny metal with pits no larger than say 1/32" diameter and about .003" deep....that is no problem.
As long as you dont have rust stains that span from the underside of the seal groove to the top of the groove.

See.....the seal is stationary. There is no sealing action in the bore. The stationary seal...seals on the piston. So as long as the bore is smooth enough to not cause drag on yhe piston when you fit it dry with no seal.....it makea no difference if there are rust pits.

However. ...the piston cannot have rust "stains" on it. After you polish the piston ....it can have small pits about 1/64" diameter maximum....and no big clouds of them in close proximity to each other.

If you find a seriously pitted piston....trade the calipers in for cores.

Now....for the adventurous rebuilder.....if you have nice calipers with pistons that have a constellation of small pits.....bear in mind....ATE pistons are plated and this is pits in the plating.
So....since technically in this condition they may be junk......get your goggles and Respirator and place the pistons in a bowl of muriatic acid for 15 minutes until they stop fizzing. When they come out...all plating AND rust will be gone and the pistons will look dull.

Polish them with 800 finishing with 2000.....and they will look like new. They will be .001-.0015" smaller in diameter which is well within tolerance and makes no difference.

Now...without the chrome plating.....they will be more susceptible to rust from water in the fluid. Just religiously change fluid every other year and watch your outer seals.

I have a zillion trouble free miles on calipers like that. Ray

Wed Aug 20, 2014 8:47 pm

I'm once again amazed Ray. AAA+

Wed Aug 20, 2014 10:39 pm

aeromech wrote: I'm once again amazed Ray. AAA+

Thank you!....its the liquor. ....

Oh...by the way your post just made me remember that you wanted some caliper internal seals. I am finally getting unpacked and can get those to you. If you have those...you can split the calipers.
I will get them out the door. I have been on the road too long. Just getting caught up. Ray

Wed Aug 20, 2014 10:46 pm

raygreenwood wrote: aeromech wrote: I'm once again amazed Ray. AAA+

Thank you!....its the liquor. ....

Oh...by the way your post just made me remember that you wanted some caliper internal seals. I am finally getting unpacked and can get those to you. If you have those...you can split the calipers.
I will get them out the door. I have been on the road too long. Just getting caught up. Ray

yes - the wine is great tonight - please keep looking for the EGR diaphragm as you unpack. Bob has not sent it back to me yet :)

Wed Aug 20, 2014 11:33 pm

porschpow wrote: I have noticed that the bus pulls to the right a little and when I brake....

Alright so back to your first post here which makes it sound like it is pulling to the right a bit at all times not just when braking? If the steering geometry is off and causing it to pull to one side, then it may pull that much worse when applying the brakes. If this is the case then find out what is out of whack with your steering/suspension.

Thu Aug 21, 2014 8:45 am

raygreenwood wrote: aeromech wrote: I'm once again amazed Ray. AAA+

Thank you!....its the liquor. ....

Oh...by the way your post just made me remember that you wanted some caliper internal seals. I am finally getting unpacked and can get those to you. If you have those...you can split the calipers.
I will get them out the door. I have been on the road too long. Just getting caught up. Ray

Great Ray, thanks.