- Thread starter
- #21
I've replaced the brake booster, and still have the issue. I'm thinking the seized caliper may be the problem. What is the seized rear slide pin you refer to?
Help Me Diagnose My Brake Issue - 97 FZJ80 (3 Viewers)
- Thread starter ColoradoLC
- Start date
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The rear calipers use slide pins to control the movement when you use the brakes. They can seize and then the calipers don’t work as intended.
Did you also replace/function check the valve on the brake booster that pulls vacuum from the intake manifold?
are you getting vacuum to the booster? your new booster came with a new check valve right?
A very hard pedal with reduced braking is brake booster/vacuum related.
A soft pedal with reduced braking is a fluid leak or master cylinder issue.
If the pedal feels normal and you have reduced braking, I'd be looking at calipers.
Brake fluid should be almost water clear. The darker it is, the more contaminated it is. It should be flushed every 2 years or so.
Calipers should be rebuilt with OEM kits. If the pistons are corroded, replace them. They're still available new.
If the cylinder walls are corroded, then replace the calipers with OEM rebuilds.
All of the bits and pieces for the calipers are available new.
I have 2 sets of calipers that I rotate every 2 years or so. Both sets have been powder coated and get a complete rebuild with all new OEM parts when off the truck. Amsoil moly grease on everything.
Vacuum sealed and sitting on a shelf ready to be installed.
A soft pedal with reduced braking is a fluid leak or master cylinder issue.
If the pedal feels normal and you have reduced braking, I'd be looking at calipers.
Brake fluid should be almost water clear. The darker it is, the more contaminated it is. It should be flushed every 2 years or so.
Calipers should be rebuilt with OEM kits. If the pistons are corroded, replace them. They're still available new.
If the cylinder walls are corroded, then replace the calipers with OEM rebuilds.
All of the bits and pieces for the calipers are available new.
I have 2 sets of calipers that I rotate every 2 years or so. Both sets have been powder coated and get a complete rebuild with all new OEM parts when off the truck. Amsoil moly grease on everything.
Vacuum sealed and sitting on a shelf ready to be installed.
- Thread starter
- #27
Yes for both. I now have a new booster, so that's is a part I won't have to replace for a while!
- Thread starter
- #28
I do change the brake fluid every couple of years and it is enough that it is usually barely discolored by the time I replace it. No air in the lines and just to be sure this wasn't the issue, I've probably run nearly 2 gallons through all of my brake lines.
You bring up good points about pedal stiffness. I'm now back to thinking it is my calipers and I like your approach to this, so I have ordered a new set of fronts for both sides. Once I get those one, I'll rebuild the old ones and have those as spares.
