Double pump/tap brake issue fixed (1 Viewer)

[SUMMIT CRUISERS]

I've read a lot of threads about this and thought I'd report my findings.
Newly acquired 99 LC with 189K. Ever since I purchased the truck the brakes are squishy on the first application of the pedal. Immediately afterwards, the second tap of the brakes result in a very firm pedal.

PO changed the front brake pads. Rear pads are somewhat thin and rotors are at 16mm with a lip around the edge. Rear rotors appear to be original.
I bled all brakes and still the same.

Last night I replaced the rear pads/rotors and found that on the driver's side one of the slide pins was stuck and not rotating easily. I finally got the pin removed, cleaned, greased and reinstalled. I then rebled the rear brakes for kicks. Did a test drive and BRAKES ARE ABSOLUTELY PERFECT NOW!

issue was obviously caused by the rubber boots on this side not being installed over the lip by the previous technician. This enabled water/dirt into the slide pin cavity that caused the pin to stick. Hope this helps out another Hundy owner.


UPDATE…SEE FOLLOW-UP POST BELOW. Issue has returned.

 

[DirtDawg]

Glad to hear that your issue was pins and not the modulator pump like others have been seeing issues with lately. I still need to come check it out..

 

[SUMMIT CRUISERS]

Update...on the above post. Brakes worked great for a few days at least then they slowly started reverting to the double pump issue. Not really an issue but on the second tap of the brakes they are extremely responsive. First applying of the pedal they are OK. Not dangerous to drive by any means.
I might try locking them up on dirt to actuate the ABS to see if that helps.

 

[suprarx7nut]

FWIW I worked at a Toyota dealership for a summer in college. I drove dozens of cars per day for an entire summer as a "lot tech" (read: dealership valet). The squishy and increasing feedback brakes were incredibly common on all the late 90's early 2000's SUVs and Trucks - and this was in 2006 or so when some of these models were pretty new. Lexus models had a similar squishy, unresponsive feel, but I don't recall ever noticing the second pump firm-up.

IMO, curing the squishy, unresponsive pedal and eliminating the second pump firm-up can be tough because the Toyota design used on these vehicles lends itself to these problems. I have no idea what parts in the system cause this to be a brand-wide phenomenon, but after driving literally hundreds (maybe even thousands) of vehicles back to back for a living I just associate that pedal feeling with Toyota truck/SUV brakes from the late 90's and early 2000's.

People on here have had mixed luck replacing the master cylinder, replacing the accumulator, replacing the calipers (or rebuilding them), but there have also been people that have replaced most the system and still had one or both problems. Thankfully, the car always stops (with the exception of the ABS pump failure problem) so the lack of feeling is just a reminder to me that it isn't a performance vehicle.

 

[wngrog]

A few guys in our club have had to replace the booster. It's brutally expensive, in the neighborhood of 4000 dollars with labor. It can't be ignored either because it eventually leads to total failure.