Brake caliper piston compressor

[MI_Roger]

I ordered an OTC 7317A brake piston kit today for an upcoming brake job on my wife's car. This caliper piston uses an unusual pattern (Saab 9-3SC) and most (nearly all) kits don't contain the right adapter. Neither does the kit I ordered, but at least it uses a 3/8 square drive so I can fit a proper pattern pro-grade adapter on it. I got an Assenmacher V450 adapter last week.

I am still baffled that there is no common numbering system for the various patterns of piston adapters, or uniformity of application. The adapter I need for her car also fits two Volvo models (but not all), the BMW Mini, but none of the other Saabs! Who decides things like this?

 

[bdcardinal]

He who counts beans.

 

[fdcg27]

Large C-clamp.

 

[MI_Roger]

Originally Posted By: fdcg27
Large C-clamp.


Nope, won't work with these. The piston needs to be rotated slightly as it is compressed because the parking brake uses the piston too.

Every other vehicle on which I have done brake jobs was only straight compression of the piston, which I accomplished with a large C-clamp.

 

[Chris Meutsch]

"Another Saab story."

I had no idea that a caliper was so complicated as I've never worked on a Saab/random Volvo or Mini. But, I learn something every day. Good luck!

 

[GeorgiaHybrid]

Originally Posted By: Chris Meutsch
"Another Saab story."

I had no idea that a caliper was so complicated as I've never worked on a Saab/random Volvo or Mini. But, I learn something every day. Good luck!


Chris, a LOT of cars use a screw in caliper now. They will have either a drun brake for a parking brake or will use the caliper piston for that function. Those that use the caliper will require a screw-in adapter to get the pistons to retract.

 

[SLCraig]

I don't know what you have in your kit, but I have one of these in the toolbox (I used on the rear calipers on my Nissan)

Every side has a different pattern, and 3/8" drive is how you drive it.

 

[buickman50401]

Originally Posted By: SLCraig
I don't know what you have in your kit, but I have one of these in the toolbox (I used on the rear calipers on my Nissan)

Every side has a different pattern, and 3/8" drive is how you drive it.

Oh the horror of using that thing to run the pistons back in on my wife's old Cougar using a 1/2" hammer drill to turn it. Still gives me nightmares

 

[The_Eric]

Originally Posted By: buickman50401
Oh the horror of using that thing to run the pistons back in on my wife's old Cougar using a 1/2" hammer drill to turn it. Still gives me nightmares

They should go fairly easy once started. Were they really hard to push back, or was it just a conglomerated mess? If it was really (physically) hard to push them back, then the piston and seal were likely partially seized and you should have replaced the caliper.

 

[38sho]

be careful on some of the newer larger Ford sedans, like the Taurus/500 lineup, some of them you have to turn the piston in counterclockwise to get it to turn in


gotta make [censored] different.....

 

[artificialist]

Originally Posted By: 38sho
be careful on some of the newer larger Ford sedans, like the Taurus/500 lineup, some of them you have to turn the piston in counterclockwise to get it to turn in

gotta make [censored] different.....

Ford isn't the only one that does that.

You should buy the book on your car so you don't make this mistake either.

 

[RH+G]

Most go in clockwise but sume global platform cars are coming out with counterclockwise calipers.

 

[mjoekingz28]

Originally Posted By: 38sho
be careful on some of the newer larger Ford sedans, like the Taurus/500 lineup, some of them you have to turn the piston in counterclockwise to get it to turn in


gotta make [censored] different.....


Right! Instead of the engineers going for durability and longevity they make the simplest things that work fine into complicated pieces that accomplish the same task.


didn't I read on here that some car company made left hand threads some time in the 60-70s.


Maybe they're trying to create business for the service department or want to sell more specialty tools?

 

[demarpaint]

Originally Posted By: mjoekingz28
Right! Instead of the engineers going for durability and longevity they make the simplest things that work fine into complicated pieces that accomplish the same task.

didn't I read on here that some car company made left hand threads some time in the 60-70s.

Maybe they're trying to create business for the service department or want to sell more specialty tools?

True! I think [not 100% sure though maybe one of our resident Chrysler experts can chime in], Chrysler reverse threaded the lug nuts back in the day. Many people cursed them when they went to change a flat and were tightening lugs when they thought they were taking them off.

 

[SteveSRT8]

Originally Posted By: 38sho
be careful on some of the newer larger Ford sedans, like the Taurus/500 lineup, some of them you have to turn the piston in counterclockwise to get it to turn in


gotta make [censored] different.....


This is nothing new. We all might need to update our manuals or something.

With internet the knowledge is out there, I'd be very cautious with any newer car if I had no manual to refer to.

 

[spackard]

'61 Buick Invicta had left-handed threads on one side of the car.
It had a great repair manual, written for English readers.
It also had things that needed lubing every 1000 miles.

 

[RH+G]

Most cars in the 50's and early 60's were left hand thread on the left side of the car and right hand thread on the right side of the car

 

[The Critic]

Originally Posted By: The_Eric
Originally Posted By: buickman50401
Oh the horror of using that thing to run the pistons back in on my wife's old Cougar using a 1/2" hammer drill to turn it. Still gives me nightmares

They should go fairly easy once started. Were they really hard to push back, or was it just a conglomerated mess? If it was really (physically) hard to push them back, then the piston and seal were likely partially seized and you should have replaced the caliper.


The problem with the cube is that it doesn't push against the piston as it retracts. The correct tool not only has the correct adapter for the face, but also, has the ability to push against the piston while it turns.

 

[IndyIan]

Originally Posted By: MI_Roger
Originally Posted By: fdcg27
Large C-clamp.


Nope, won't work with these. The piston needs to be rotated slightly as it is compressed because the parking brake uses the piston too.

Every other vehicle on which I have done brake jobs was only straight compression of the piston, which I accomplished with a large C-clamp.

Can't you put a dap of grease where the c-clamp contacts the piston? To allow it to rotate?

 

[AcuraTech]

I've found that a good shot of penetrating oil around the piston seal helps for a smoother retraction process. Not quite as hard on the wrists. Easier on the seals too.

Don't use WD-40. That's not a penetrating oil. Zep 45 is awesome if you can find it. PB Blaster is good too.