How To Diagnose and Replace a Faulty Caliper

[EricTheCarGuy]

I feel this is a fairly straightforward video but I welcome your comments.

Topic

[celticbhoy]

Great video. I brought my car into class to bleed the brake system but had to replace my front passenger side caliper. Bought one but the banjo bolt wouldn’t grip the threads so I had to get another one. Just a note on the copper washers, if the caliper you previously have on only has copper washers and the new one only comes with copper washers, you can decrease the chance of leakage by tightening the banjo bolt up, then backing it off, then tightening it again. Do this 3-4 times and the copper washer will compress and settle into the grooves. Works great.

[Patrick S]

Eric,

I have worked extensively at an OEM caliper supplier that makes many calipers that are similar to the design you have on your Subaru.

If you knew that the caliper was bad beforehand (I would always use the C-clamp to push on the piston always so the piston-pad contact surface does not get damaged), I would remove only the banjo bolt and let it drain (use a catch pan). Then if there is clearance, I would loosen and remove the bracket bolts only and not touch the caliper.

When it comes to install the new caliper (once again if you had clearance to get at the bracket bolts with the caliper housing installed on the bracket), I would check the pin lubrication by sliding the pins out of the bracket on the bench without loosening. Once I was satisfied, I would install the shims and pads in the caliper through the rotor clearance with the caliper assembled to the bracket. This is how it is done @ the manufacturing plant when the calipers are made. You would then be able to slip it over the rotor and tighten only the bracket and banjo bolts. For someone like yourself who needs to do this as fast as possible for income, this would be the best way. It also makes it less likely that antisieze or silicone paste gets on the rotor surface.

Also, while your trick for the axle nut and lug nut worked well, I would suggest using an open end lug nut (many GM cars use these on nearly every car), and turn it around backwards so the hex is facing the rotor and tighten it hand tight. You’ll be able to get it off no problem afterwords as well.

I understand your dislike of the copper washers, but I can honestly say they do work well, but require more torque to crush them.

I would suggest everyone use torque specs on the bracket bolts unless they cannot find it. There are some cars (1st gen GM “W” cars like Luminas, Grand Prixs) that use a torque spec that is 125+ lb-ft on the bracket bolts. Its really not fun if these loosen up and really bad if the bolt falls out, which is worse on those cars with 16″ wheels and a 14″ brake package.

I’m not being critical at all, just pointing out things from my experience. This vid should still help many people.

[Alex]

Regarding the slider pin lubricant;

I have been using the CRC synthetic brake and caliper grease for a few years now. It says it won’t harm rubber parts on the back of the label. I haven’t had problems, but then, that dosent mean that it’s right.

Wondering if CRC is an appropriate equivalent.

I’ll be switching over to the 3m, just don’t know if I should be making an order tomorrow or if I should just wait till my current CRC bottle runs out,

http://www.amazon.com/CRC-Synthetic-Brake-Caliper-Grease/dp/B003NTNPAW

“contains moly, ptfe, and graphite”
“unlike silicone based greases, it will not damage rubber or plastic components, freeze, melt, or wash out”
“applications: … … Caliper slides, bolts & pins… …”

What do you guys think?

[Yannick Evenas]

Eric,
In what instance would you refurbish it by replacing the seals in the piston chamber instead of replacing the whole caliper?

[EricTheCarGuy]

[quote=”scha7530″ post=48018]Eric,

I have worked extensively at an OEM caliper supplier that makes many calipers that are similar to the design you have on your Subaru.

If you knew that the caliper was bad beforehand (I would always use the C-clamp to push on the piston always so the piston-pad contact surface does not get damaged), I would remove only the banjo bolt and let it drain (use a catch pan). Then if there is clearance, I would loosen and remove the bracket bolts only and not touch the caliper.

When it comes to install the new caliper (once again if you had clearance to get at the bracket bolts with the caliper housing installed on the bracket), I would check the pin lubrication by sliding the pins out of the bracket on the bench without loosening. Once I was satisfied, I would install the shims and pads in the caliper through the rotor clearance with the caliper assembled to the bracket. This is how it is done @ the manufacturing plant when the calipers are made. You would then be able to slip it over the rotor and tighten only the bracket and banjo bolts. For someone like yourself who needs to do this as fast as possible for income, this would be the best way. It also makes it less likely that antisieze or silicone paste gets on the rotor surface.

Also, while your trick for the axle nut and lug nut worked well, I would suggest using an open end lug nut (many GM cars use these on nearly every car), and turn it around backwards so the hex is facing the rotor and tighten it hand tight. You’ll be able to get it off no problem afterwords as well.

I understand your dislike of the copper washers, but I can honestly say they do work well, but require more torque to crush them.

I would suggest everyone use torque specs on the bracket bolts unless they cannot find it. There are some cars (1st gen GM “W” cars like Luminas, Grand Prixs) that use a torque spec that is 125+ lb-ft on the bracket bolts. Its really not fun if these loosen up and really bad if the bolt falls out, which is worse on those cars with 16″ wheels and a 14″ brake package.

I’m not being critical at all, just pointing out things from my experience. This vid should still help many people.[/quote]

Thanks very much for your input.

[EricTheCarGuy]

[quote=”SK40170″ post=48233]Regarding the slider pin lubricant;

I have been using the CRC synthetic brake and caliper grease for a few years now. It says it won’t harm rubber parts on the back of the label. I haven’t had problems, but then, that dosent mean that it’s right.

Wondering if CRC is an appropriate equivalent.

I’ll be switching over to the 3m, just don’t know if I should be making an order tomorrow or if I should just wait till my current CRC bottle runs out,

http://www.amazon.com/CRC-Synthetic-Brake-Caliper-Grease/dp/B003NTNPAW

“contains moly, ptfe, and graphite”
“unlike silicone based greases, it will not damage rubber or plastic components, freeze, melt, or wash out”
“applications: … … Caliper slides, bolts & pins… …”

What do you guys think?[/quote]

I’ve used silicone paste for years without incident. Most calipers come OE with silicone paste lubricant. Mixing lubricant’s is not a good idea as it changes the chemical make up of both substances and can cause problems. Honestly I don’t have any experience with the lubricant you mention but I see little need to try other things since silicone has worked so well for me in the past.

In summary, I’d say use what works for you but if you’re asking me silicone paste is the way to go.

[EricTheCarGuy]

[quote=”Yannickevenas” post=48429]Eric,
In what instance would you refurbish it by replacing the seals in the piston chamber instead of replacing the whole caliper?[/quote]

I would only recommend that if you could not find calipers or the calipers were prohibitively expensive. What I often run into is the piston and bores of the caliper get corroded and need to be refurbished. Once you commit to that it would have been cheeper to purchase an already refurbished caliper.

BTW Friday’s video will be the dissection of one of the calipers in this video.

[Anonymous]

Is that snap on wrench in the video a 3/8 drive or a 1/2 drive?

[danwat1234]

When you were bleeding the brakes with pedal action, don’t you have to push down the pedal and keep it down, then close the bleeder, then release the pedal, open the bleeder and push down again, close the bleeder and then let the pedal back up?
When the pedal is released, old fluid from the bottle gets sucked back into the line, right?
So how does that get rid of the remaining air? Why not gravity bleed until no more air instead of just gravity bleeding for part of the procedure?
Thanks. See http://www.youtube DOT com/watch?v=vOiHgP33CM4 at 26 minute mark

Your site fails at attempting to self embed youtube videos

Also, why use anti-seize on the specified corners of the brake pads, but not the same silicone paste you used on the slider pins. Doesn’t work as well as petroleum based anti-seize for brake pad quietness?

[Veiko]

Eric, sorry for posting here but since there is no video about hoses, i want to ask what you think about the next problem as experienced mechanic.

Short story: i had sticky calipers, cleaned, rebuilt with kit, put back, all OK.
Bleeded brakes and suddenly when engine starts brake pedal sinks to the floor.

Tried bleeding again, pumped 3 litres of fresh fluid through the system etc etc, nothing.
As soon as engine starts pedal sinks.

Then bleeded master, watched how you did it etc. Just tried on the car first.
Nothing changed.
Decided to take it off, took it apart, cleaned from inside and outside, a bit new brake fluid on bushings and inside, put back together, bench bleeded many times, mounted back on the car, bleeded, started car, pedal sinks to the floor. So nothing…

Found a tip online to squeeze all 4 flex hoses on car with vise grips and press pedal, after each test remove one vise grip and press pedal again to see if its still hard or sinks.

Removed all 3, until then pedal was rock hard, even with engine running.

Got to the last fourth one, thats the caliper with broken bleeder i have talked about previously.
Ok, pedal is rock hard atm, 3 vise grips removed.

Now final grip to remove from FRONT RIGHT flex hose.
As soon as i removed that final vise grip the pedal sinked to the floor.
Put the vise back and pedal was hard again.

Swapped the right/left caliper, nothing changed. Still only front right hose.
Tried other hoses, nothing changed. It was just the front right hose that always changed, if pedal sinked or not.

Yes i squeezed the front right and didnt squeeze the front left, pedal was still hard.
Right one was only guy what changed things.

I was not very gentle with these hoses when removed calipers for rebuilding and then bleeded them.
So i guess i killed one of them.

It was too late, i couldnt swap the flex hose, i wanted to put right one to the left and left one to the right, to see if problem goes to the front left.

Tomorrow i will test.

So what you think guys here? Wtf is that? Bad hose?
I used 2 bolts and closed master outlets (2 of them) with these bolts. The pedal was rock hard, even with engine running.
As soon as i removed bolts and connected the actual 2 lines that go the wheels the pedal sinked.

Yes, i did hold my leg on pedal for very long time, it didnt sink slowly or not even a litte bit.
Just the free play the pedal must have.

And i found out that mysterious hose that plays there.

Thanks guys and please share any of your thoughts on this thing. Every little bit will help.
The store gave me 3 days to figure out whats wrong and if its bad master they will get it to me.
But its very expensive and maybe i can get done just with flex hose.

[EricTheCarGuy]

[quote=”ericg72391″ post=52242]Is that snap on wrench in the video a 3/8 drive or a 1/2 drive?[/quote]

3/8

[EricTheCarGuy]

[quote=”danwat1234″ post=58786]When you were bleeding the brakes with pedal action, don’t you have to push down the pedal and keep it down, then close the bleeder, then release the pedal, open the bleeder and push down again, close the bleeder and then let the pedal back up?
When the pedal is released, old fluid from the bottle gets sucked back into the line, right?
So how does that get rid of the remaining air? Why not gravity bleed until no more air instead of just gravity bleeding for part of the procedure?
Thanks. See http://www.youtube DOT com/watch?v=vOiHgP33CM4 at 26 minute mark

Your site fails at attempting to self embed youtube videos

Also, why use anti-seize on the specified corners of the brake pads, but not the same silicone paste you used on the slider pins. Doesn’t work as well as petroleum based anti-seize for brake pad quietness?[/quote]

When using the ‘bleeder bottle’ you don’t need to worry about the air being drawn back into the system because the end of the hose is immersed in the fluid. It will only draw fluid back in. After a few pumps enough fluid will have come out so that you don’t have to worry about the old fluid being drawn back in.

The site embeds videos just fine. The people that complain about it not working usually have a browser issue or they need to do an update.

Different brake parts require different lubricants. Petroleum based anti-seize tends to dry up on brake applications in my experience. I’m not saying YOU can’t use them, I just find what I use to be most effective.

[EricTheCarGuy]

[quote=”venge” post=66700]Eric, sorry for posting here but since there is no video about hoses, i want to ask what you think about the next problem as experienced mechanic.

Short story: i had sticky calipers, cleaned, rebuilt with kit, put back, all OK.
Bleeded brakes and suddenly when engine starts brake pedal sinks to the floor.

Tried bleeding again, pumped 3 litres of fresh fluid through the system etc etc, nothing.
As soon as engine starts pedal sinks.

Then bleeded master, watched how you did it etc. Just tried on the car first.
Nothing changed.
Decided to take it off, took it apart, cleaned from inside and outside, a bit new brake fluid on bushings and inside, put back together, bench bleeded many times, mounted back on the car, bleeded, started car, pedal sinks to the floor. So nothing…

Found a tip online to squeeze all 4 flex hoses on car with vise grips and press pedal, after each test remove one vise grip and press pedal again to see if its still hard or sinks.

Removed all 3, until then pedal was rock hard, even with engine running.

Got to the last fourth one, thats the caliper with broken bleeder i have talked about previously.
Ok, pedal is rock hard atm, 3 vise grips removed.

Now final grip to remove from FRONT RIGHT flex hose.
As soon as i removed that final vise grip the pedal sinked to the floor.
Put the vise back and pedal was hard again.

Swapped the right/left caliper, nothing changed. Still only front right hose.
Tried other hoses, nothing changed. It was just the front right hose that always changed, if pedal sinked or not.

Yes i squeezed the front right and didnt squeeze the front left, pedal was still hard.
Right one was only guy what changed things.

I was not very gentle with these hoses when removed calipers for rebuilding and then bleeded them.
So i guess i killed one of them.

It was too late, i couldnt swap the flex hose, i wanted to put right one to the left and left one to the right, to see if problem goes to the front left.

Tomorrow i will test.

So what you think guys here? Wtf is that? Bad hose?
I used 2 bolts and closed master outlets (2 of them) with these bolts. The pedal was rock hard, even with engine running.
As soon as i removed bolts and connected the actual 2 lines that go the wheels the pedal sinked.

Yes, i did hold my leg on pedal for very long time, it didnt sink slowly or not even a litte bit.
Just the free play the pedal must have.

And i found out that mysterious hose that plays there.

Thanks guys and please share any of your thoughts on this thing. Every little bit will help.
The store gave me 3 days to figure out whats wrong and if its bad master they will get it to me.
But its very expensive and maybe i can get done just with flex hose.[/quote]

This is the reason I don’t recommend rebuilding calipers. There is much that can go wrong. If I were to guess what the issue is, I would guess it’s something to do with the caliper.

[Veiko]

Maybe, but i took right caliper and put it to the left and left to the right.
Problem was still at right.

Of course i should replace them, but maybe i can just replace hose atm and will be ok.
Who knows. I dont even know how much the hose will cost.

I know how it will gonna be, i replace the hose or hoses, then the next thing goes lol.
And the whole vacation of mine just goes into repairing of the car.
I cant drive anywhere.

[Veiko]

Eric
I ask you as very experienced mechanic. I dont have anyone else to ask. No friends no mechanics.

I swapped the hoses and bleeded the brakes and i still have this problem. Now i have that problem on the left also but not as much as in right side.
If i just squeeze front right hose the pedal gets hard when idling, but not so hard. Still falls like 3-4cm into floor.
But if i also squeeze the front left hose then its completely rock hard.
Previously it was only front right that changed this.

I looked at the bleeders and wheels, i dont see leaks. Fluid doesnt disappear anywhere.
The rear drum brake cylinders leak a bit (if i remove their dust cap slightly), i can see a little bit of fluid there. But nothing big.

I ordered 2 new front hoses, they were cheap, it will take 2 days before i get them and when i will get i will replace immediately. I dont know if it will change anything or not, but at least i can tell that its not the front hoses fault.

[u]Pumping the pedal when engine is running reduces the pedal sinking. And it stays at this position until i release the pedal, wait a bit and then press again, then it sinks again.
If i pump it again reduces the amount how much pedal sinks.[/u]

So Eric imagine i would get the car to your shop with new hoses and bleeded system.
And pedal still sinks when engine runs.

What would be the next thing you would do or try?

I must tell you that im very tired, frustrated and disappointed, i just dont know what else to do.
Sometimes i just want to dump this car, wash my hands and thats all.
But i have replaced so many things in it, it drives really well, i want to try to clean the injectors that hopefully removes the little hesitation it has etc..

But the brakes. 2 weeks wasted and nothing, they just get worse.

Please Eric, tell me what you would do next in your shop on this car?
You may say, replace the master, but if after that pedal still sinks?

Thank You for all the previous help Eric.

[Author]

Replies