Brake issue...HELP!!! 1988 Itasca 423RC

[88itasca460]

Hello everyone. I have a ford chassis 88 24ft itasca. One day all of a sudden I had very little brake pressure but could drop if i pumped them before needing them, but barely. And they sounded like they were sucking air from right behind peddle.So after inspection I noticed a few things:

1) the vacuum line had a couple chunks taken out of it.
( possible vacuum leak)

2) the oil dipstick had rubbed a tiny hole in outer booster casing
( but there was no pressure coming out when pumping brakes or sucking when pedal released. So thinking this is cosmetic. )

3) I am not losing fluid... all wheel cylinders are dry and no visible signs of busted line or blown seals...

So I replaced vacuum hose from intake and verified check valve is functioning. Bled brakes starting furthest away and working towards master cylinder. Brakes would harden as expected but when I switch to next brake it is right back to woosh... straight to the floor... gradually gets hard... then back to soft and airy when move on to next one. Finished bleeding all 4 and now instead of sawoosh and to the floor and getting a little pressure if pumped when I press the brake pedal it goes down slightly then its like hitting a hard spongy wall that gives but does nothing anymore to slow you down.


Any ideas??

New calipers in front and rear brakes look fine.


Thanks in advance

[Ray,IN]

Does your chassis have hdyroboost brakes? This irv2.com thread may be helpful: https://www.irv2.com/forums/f23/f53-brakes-487977.html


FWIW, irv2.com( and their Winnebago forum) is over 10 times larger than this little sister website, therefore you have a much better chance of getting more replies.

[Bobn1957]

It sounds to me that your master cylinder has failed, the whooshing sound would be the vacuum booster trying to help. IMHO