catastrophic brake failure

[Europa73]

Word of warning.

I thought I would take the car to work today –

Hi-way then driving in the city.

All going well then – in the city the brakes fail completely with no warning –

Swerve to miss the car in front then I roll to a stop!

Catastrophic brake failure.

The issue was – the split pin had failed and the round pin holding the pedal to the master cylinder push rod had slipped out.

Check that pin!!!!!

Popped it back in and limped to the office

That really freaked me out!!!!

[BDA]

Yikes! I'm glad neither you nor your car got hurt. That could have been really bad!

You might even ditch the pin arrangement all together and replace it with a bolt and a lock nut.

[Grumblebuns]

Must have been a good exercise on sphincter muscle. Was it a new cotter pin? The clevis pin is usually a slip fit on the brake pedal to the pushrod so trying to figure out the failure mode.     

[Bainford]

Very glad all ended well. Many thanks for the heads up, I'll be checking as soon as I get home.

[Europa73]

The offending split pin goes into the hole in the locking pin (number 5) in the diagram.

This then secures the brake pedal in place.

Having this fail did put me into pucker factor 7 and almost achieved full code brown!

If this happened only a few mins earlier - would have been on the highway!!!!

[jbcollier]

How did the split pin fail?  I have never seen one fail unless there was some other issue.

[Europa73]

hi there - at this point I have no idea - when I get home I will find the little thing and see what went on.

[4129R]

Who put the split pin in place?

If they used a non-rusty pin and splayed the two parts properly, it cannot come out.

If they changed it for a P clip, and it was not a tight fit, it can slip off.

[jbcollier]

Split pins are soft steel and should have a washer when used next to moving parts.  If the brake linkage is not in perfect alignment, and virtually none are, then a sideways force is applied to the clevis pin.  This could cause the motion of the brake linkage to wear through the split pin. Thus the need for a protective washer between the split pin and the brake pushrod.

[rfgumby]

Hello,
I know how you felt! I had the same problem a few years back. Fortunately it was an a Autobahn on which a whole lane was closed because of works and I could get onto the closed lane and had mach space to let it roll to a stop.

Uwe