2008 Mazda Tribute master brake cylinder
 

Hi,

2008 Mazda Tribute v6 FWD automatic
180,000km

Infrequently, over a period of eight months, the brake pedal would travel to the floor.
This happened maybe three times.
I took the truck into Canadian Tire. The Canadian Tire mechanic said that fluid was blowing by the piston and the master brake cylinder needed to be replaced.
Soon after, the rear brake drum cylinders were replaced.
Fast forward three months.
My son was driving the Tribute when the brakes completely failed, with the brake pedal traveling to the floor
To avoid an accident, he drove off the road, onto the curb and hit a road marker.
He parked the truck and I picked it up the next day and delivered it to the same Canadian Tire that serviced the vehicle three months prior.
After looking at the truck, Canadian Tire reported that the brand-new master cylinder they installed in October 2018 had failed.
The master cylinder is under warranty but I am being charged the cost of installation ($250).

Obviously, this is a significant safety issue.

Questions:
Are the master cylinders in 2008 Mazda Tribute's prone to failure?
Is failure related to poor aftermarket brands or are there other mechanical issues with the 2008 Mazda Tribute that may lead to brake failure?
I am waiting to find out what cylinder was used in October (I paid for a new master cylinder and not a rebuilt one), but is there an aftermarket brand I should avoid?

Thanks

Master cylinder failure is pretty uncommon in any vehicle, it would be hugely unlucky to have two such failures so close together.

Personally I'd replace the master cylinder with a manufacturer part after having a dealer confirm that the ABS pump/valves are working correctly as it is possible that has been the cause all along, still pretty unusual but more likely than two master cylinder failures IMHO.

Thanks simonsi,

Yes, master cylinder failure is pretty uncommon. I am trying to trouble shoot this.I relied on the expertise of the auto centre but now have my doubts about their expertise.
This is a significant safety issue.
I have an OBDII code reader and I will hook it up once the work is done.

Hi all,

The brake pedal went back to normal after a short period of time. But my son had to slam on the brakes to avoid a car, ABS kicked in and now the pedal is soft again.

As previously stated: the master cylinder has been replaced twice, brake booster replaced, all four corners cleaned.

I now have the truck at the local Mazda dealership.

Mazda ran diagnostics but there are no idiot lights or codes being thrown to suggest an ABS failure.

However, they recommended I replace the ABS module.

They have replaced and same soft pedal/weak braking problem remains. Still no idiot lights or codes.

Any other suggestions? Would faulty wheel sensors cause soft braking? Is the main ECU fried - Mazda says it still scans properly ...

Perplexed

By “soft” do you mean long travel before the brakes start to engage or spongy feel once they have engaged?

Long travel, mushy, spongy.

I have been reading and it seems there are issues with tone rings (tooth ring next to CV joint that the ABS sensor reads) I am going to suggest the dealer take a look at these if they haven't already.

Anyone else with tone ring issues?

So assuming everything that should be fastened securely is, then that can only be mechanical/hydraulic (inc air in the system). My guess is it isnt being fully bled and once the ABS pump cycles it is introducing air into the static system.

Tone rings are an issue but false/no tone signal will alter when the ABS triggers, not affecting pedal feel when is isnt being triggered. Same for the ECU.