Autozone master cylinder problems - Toyota Nation Forum : Toyota Car and Truck Forums

k3eax · 07-31-2007, 06:55 AM

I've had problems with two Autozone master cylinders; one a re-built and the other a new manufacture. Each caused the pads to squeel after a few miles of driving. I suspect the master cylinder did not permit a full retraction of the pads and caused them to over-heat. My theory is that that the cylinders were not spec'ed to match the brake booster's pushrod length --- that pushrod extending too far into the cylinder.

The pushrod end is suposed to have clearance with the master cylinder's primary piston. I did not measure this clearance prior to installation.

I would like to hear from others who have had similar problems with Autozone master cylinders

1sweethellica · 07-31-2007, 07:04 AM

your lesson is learned never buy from autozone for your yoda ever

either go to orielly's or yota them selves

k3eax · 07-31-2007, 07:18 AM

Thanks for your reply but I can't agree with your contention as I've gotten very good service-life from Autozone parts and their typically guarenteed for life.

I posted because I'm not sure that the cylinder was at fault and so was seeking others with a similar problem. If there are other with a similar problem it would indicate a pattern failure due to an out of spec manufacturing defect.

steppinthrax · 07-31-2007, 07:30 AM

This is a non-abs system right??? go to the junkyard and get a master cylinder there. At least it's OEM and it would be cheap.

k3eax · 07-31-2007, 08:26 AM

Sorry, but I can't agree with you on using a slavaged part. The reasons are many; its condition is really unkown, it may hve been sitting in yard for a long period of time and becuase it wasn't used rust could weel develope about the bore in the vicinity of the primary piston, it may or may not be an OEM part, my life depend upon it.
I'm seeking confirmation that this problem is a pattern with Autozonne cyclinders; and if it is , I will remove cylinder and measure pushrod to primary piston clearance.

Al, A.S.E. Master Auto Tech/L1

***Your Uncle Moe*** · 07-31-2007, 08:45 AM

Are you sure that your problem isn't from worn pads, disc? Have you grease the pins in your calipers lately? 3 weeks ago I had the same problem and for years I thought it was the brake pads and disc but turns out that they just needed to be greased and the calipers were stuck.

steppinthrax · 07-31-2007, 11:36 AM

Quote:

Originally Posted by k3eax

Sorry, but I can't agree with you on using a slavaged part. The reasons are many; its condition is really unkown, it may hve been sitting in yard for a long period of time and becuase it wasn't used rust could weel develope about the bore in the vicinity of the primary piston, it may or may not be an OEM part, my life depend upon it.
I'm seeking confirmation that this problem is a pattern with Autozonne cyclinders; and if it is , I will remove cylinder and measure pushrod to primary piston clearance.

Al, A.S.E. Master Auto Tech/L1

When you went to autozone did you get the cheapest cylinder or the most expensive. Did you take the time to examine the difference between the oldest and newest. If you know how to "read" a car you can easily see if it's a good idea to pick a part or not. I've gotten great parts from yards that were practically brand new. If brake fluid is in the resevior and it's not black it should be fine. You know you can also mostly overhaul or take apart a master cylinder.

k3eax · 07-31-2007, 12:23 PM

I'm quite familiar with Autozone's offerings. Their re-built master cylinders are all over-bored and then steel sleeved as are their new cylinders.

Pad noise due to improperly lubricated slides reveals itself to the diagnostician in other ways, like excessive inboard pad wear. And, I can assure you that all proper installation proceedures were followed.

A salvaged cylinder is like playing Russian roulette. Clear fuid and relative lack of exterior muck matybe an indiaction of a recently rebiuilt cylinder. Then again any cylinder, new looking or not, maybe the reason why the car is in the salvage yard! I've been repairing cars for five decades and have never used salvaged brake parts and never ever will.

Again thanks for taking the time to reply.

'Still waiting f to hear from someone with AZ master cylinder problems.

***toyomoho*** · 07-31-2007, 12:53 PM

Might check the caliper piston seals.

k3eax · 07-31-2007, 02:01 PM

The caliper square-cut seals are replaced by me every other pad change; besides, it would bw extremely unlike for BOTH calipers to go south SIMULTANEOUSLY.

Perhaps i should also tell you that the problem occured immediatelty after I replaced a perfectly functioning original cylinder at 80,000. I always replace master cylinders BEFORE the go bad and 80K is reasonable l service-life expectancy.

I know that the replies are well meaning but I,m really looking for to hear from some one has experienced a similar problem after using an AZ master cylinder replacement.