Can't get my front caliper off...need some help
 

Hi everyone,

PO had a brake job done way back. When they put the caliper back on, the brake hose was twisted. So I want to untwist it.

I take the caliper bolts out, and try to pull the caliper off. It wont come off. I inspect the rotor and see a large lip that has been worn into the outside edge that is blocking me from taking the caliper out.

My questions:
1.) Is the lip supposed to be there?
2.) Any ideas how to get the caliper off over this lip thing?

Figure 1 - the twisted brake hose
Figure 2 - the lip. My finger is pushing on it. Id guess its about .080" (2mm) tall.


Thanks so much,
dd44

Yes, the lip is supposed to be there.

Compress the pistons with by pushing the pads back as if you were going to change them.

Don't forget to put some loctite on those caliper bolts when you put them back in.

If the lip is anywhere near that high, your rotor thickness is likely not within service limits.

A new rotor has no lip. The lip is the result of the rotor wearing under the pads.

Get a flat, heavy duty screwdriver and pry the pad open to clear the lip...

You dont have to take the caliper off if you just want to untwist the hose. You can loosen it from the other end.

That's right, brake hose replacement (or adjustment) does not require removal of the caliper. When you loosen the line at the top where it connects to the hard line, it is the hard line nut that turns. Once that is loose or off, you then can turn the brake hose in the caliper with no restriction.

That's about the only way to accurately get the brake hose installed without any twist.

Ken300D

It's probably a good time to flush the system with new fluid anyway.

1.Open bleed screw.
2. Push pistons back.
3. remove caliper.
4. Buy more DOT 4 fluid and flush the system.

I'd replace that brake hose, they don't like to twist it will probably leak.

But then you have to bleed that brake. It's easier to just remove and reinstall the caliper. (Assuming that the hose was installed straight originally.)

There should be no need to turn the hose in the caliper. It is threaded, so any turning will either tighten or loosen the hose. Turn the other end after removing the line fitting.

If this is so ( "way back") and the hose has been operating twisted since "way back". I would really recommend replacing the hoses. ( yes all of them) they do not like to operate in a twisted mount. You probably have deterioration of the hose. You would hate to have the hose fail.

A couple of comments. To remove the caliper you will need to push the pads back from the rotor. To do this you can either open the bleed screw and allow the fluid to bleed off into a jar, via a hose, as you push the pads back away from the rotor with a large screwdriver. Once both are "retracted" you should be able to remove the the caliper. The second method is press on the pads with the screwdriver and allow the fluid to flow back into the reservoir. Remove some fluid first. I prefer the first method.

The lip is caused by the pads wearing down the rotor, this is normal, but the thickness of the rotor should be measured to make sure the rotor has not worn too thin. If the rotor is too thin an application of the brakes can push the pistons out of the caliper and cause a leak and/or system failure.

The hoses can be removed while the calipers are on the wheel hub. Use flare wrenches so you don't round over the hose ends.

All the operations should be followed with a system fluid bleeding. It is possible to have air enter the system while doing any of the above operations. Plus if the system is in a "way back" status. The fluid has probably absorbed water and could be rusting out your steel lines, You don't want to have to replace the steel brake lines. A huge job.

So

Replace the hoses.
Measure the wear of the rotor, replace if to thin, ( minimum thickness 10.6mm )
If replacing the rotors, replace the pads and hoses. And repack the bearings
Flush and bleed the brake fluid, no matter what the outcome of the above.

Another item. When installing the hoses the twist should have been eliminated. This is done by installing the caliper, then the hose to the caliper. Any "twist"is eliminated when the hose is attached to the hard steel line at the wheel well. Since the steel line connector is a free rotating connector you position the hose correctly and then tighten the 2 with 2 flare wrenches while keeping the hose in a good position.

Dave

Looks like the caliper was installed without the hose attached and the twisting was due to the hose being forced into the caliper. You have a 1 in 360 chance to get it straight(+-5 Deg). You will still have to open the bleed screw to move the pistons and therefore have to bleed it to make sure there is no air.

You can file out a portion of the lip if it is still hard to remove.

Nothing wrong with that.

Incorrect.

You won't find that procedure in the service manual!!!

If you remove the pad retention pins, you can slide the caliper off, leaving the pads behind. That way the pads don't have to slide over the lip.

Gloves? Your a manly man arent ya? xP joking of course, yeah the lip is supposed to be there.

So...would it be a problem if there were no lip? Why is the lip supposed to be there?

Because the rotors have time on them. New rotors=no lip.

My rotors have about 30k miles on them and have a nice lip. The ratio on MB front rotors seems to be two sets of pads per set of rotors. You don't turn them just replace.

Some people should not be let near cars to service them, like the PO who didn't see, or is too stupid to realize, the lines or writing on the brake hose used to show if the hose is twisted.

The brake pads squeeze on the rotor INBOARD of the edge of rotor, causing a ridge on the outter most edge.

If that is easier for you than loosening the other end of the hose and by all means go for it.

Wow, thanks for all of the replies
 

Thanks for all of the replies. Glad to see the lip is okay. I agree I don't want this hose failing on me.

I just bled my entire brake system a couple of months ago when I replaced my rear hoses and vacuum booster. Shame on me for not seeing this twisted hose until it was too late. I was too occupied with the other portions of the job.

Okay, onto the solution. Looks like I may be in for some front rotors, I need to measure those first. I will put in new front hoses, like I should have done from the get go. I was trying to get away from my 'compulsion to over-repair'.

Questions:
1.) Do I need to bleed the rears if I am only messing with the fronts?
2.) Do I need to bleed the MC by itself with the steel lines disconnected (like I did when I removed it) or can I just bleed from the caliper bleed screws the whole time?

Thanks,
dd

I knew someone would comment on that :-)

1. The front and rear systems are separate, so there is no need to bleed the rear brakes.
2. Bleed at the calipers only. Don't touch the lines at the master cylinder.

Nice, thanks. Not so bad compared to the full bench bleeding proceess when removing the master cylinder :)

It's front brake job time!
 

Measured my front rotors, they were down to 7mm (wear limit is like 10.6mm). So, the car did not move another inch. The pads look okay. I am not going to replace those, just the rotors. Any inherent problem in doing this?

And of course I got some new hoses as well, which started this whole adventure.

dd

No problems installing just new rotors.

NO Problems? what world do you live on?
123 front rotors are a Royal PIA...
ya have to pull the hub off the spindle, which requires cleaning and repacking the bearings.
you have to pull all those tiny 10mm allen bolts to get the rotor free from the hub (better get the hub bolted to a tire and use it to aid with leverage for that) then you have to clean off all the old loctite and put new on, or replace the bolts with new MB pre loctited bolts...
I find nothing simple about that!

Sorry to confuse, I was referring to reusing the pads he just put in. It is a lengthly job for rotors, as you have pointed out. And if he puts new hoses in, a bleeding is in order... more fun. BTW, the service limit for the rotors is 10.6mm, and 2mm per pad, bringing the total to, and I flunked math, 14.6mm. Your new pads will have more depth, buying you some driving time.

OH NO I didnt know Id have to do all that!

Wonderful...oh well small price to pay for the car stopping. Im getting new pads then, screw it, Im doing this once and not touching it again for the longest amount of time possible. For all I know the pads arent correct.

dd

Don't feel bad, tomorrow I am checking out our 300D's front brakes....the rotors look OK :D from looking through the wheels (no visible lip...) but the pad warning light is on solid as of 2 weeks ago, so it needs them bad, they're getting real close to the rotor. I have a set of new pads, but no rotors...hopefully the rotors are still serviceable....else I'll be doing it the following weekend. ;) The front brake job isn't all that bad, its just a lot of steps and the greasing of bearings is annoying. I bet moving quickly you could acomplish both sides in 2.5-4 hours. Inexperienced maybe 4-6 hours.... Good luck! :)

Wheel Bearings
 

So is wheel bearing pulling and repacking a DIY without those fancy tools in the FSM? Is there a 'practical' guide for doing this job somewhere?

How much is this job at an indy? Winter is coming and I need this stuff squared away...

dd

It is not too bad as a DIY project. The only special tool I can tink of is the allen socket and a good 1/2 inch breaker bar to remove the cap screws on the back side of the rotor to separate it from the hub.

You may need a "torque amplifier" which is a piece of iron pipe to slip over the end of the breaker bar to make it longer and have better leverage. Some people have had trouble holding the rotor still while breaking the bolts loose. I put mine face down in a wheel that was laying flat on the ground to secure it. I think others have used a big vise!

If your pads are practically new it will be ok to keep them. They are EASY to change later. The rotors are the PITA. Remember to put some Loctite on the rotor bolts when you reassemble everything.

Rotors R Us...
 

DD,

For the 123's at least, it will become a regular DIY maintenance work element to do R&R on the rotors. I mic mine per spec. Some folks just go with one R&R per two sets of front pads.

Check several threads in this forum on How-To, one to which I contributed a little.

Tips I would add:
+ go only with quality rotors
+ if you do the rotors, do the bearings and new seals (ditto quality only)
+ if you do the bearings, do the races (they come with the bearings as a kit)
+ to smack out the old races, go to a metal junk or recycling yard and ask for about a 12 inch long piece of 1/2" diameter round brass stock. Don't use steel (come guys use large screwdrivers), or you might score up the adjacent metal on the hub.
+ use the old race over the new as a tool for tap-tap-tapping in the new race.
+ greasing the bearings is only messy if you make it so. Nitrile gloves and rags, a good knuckle pinch technique, and each can be done in maybe 45 seconds, full up.
+ the big check will be adjusting the bearing tightness. Again, see the threads. Important task. I do it, then check again after two days of driving.

Do the job once and you will have the confidence to go again.

PS. While in there, don't forget to check on all the linkages, leaky boots, damper, etc.

Good luck.