question Help and advice urgently needed

Good morning all,as some of you know we are the owners of Jacks old "jimmy".

Now on the whole,most thing are ok.over the last few months we have been sorting out the rot in the cab area(all stripped)

So now started to rebuild it,its been parked up for a couple of months and yesterday when we moved it "under its own steam"................................................HELLFIRE,no brakes.(pedal goes to floor)

I've done a quick search on here and discovered that Jack had some braking issues in 2008 which resulted in all new wheel cylinder's,shoes and finally a trip to Rex Wards place and new seals fitted to the hydravac unit.Jack states that after this the brakes worked ok.

So question................with a very "soft pedal" and no brakes where do we start looking and testing. Would it be normal to have to re do the brakes again after a short period.

Thanks in advance,I'm sure we will get some positive help and IF we make it to W&P the chocolate biscuits and coffee will be on us,thaks guys.

Gary/Steve

Unfortunatley, yes brakes can go after a very short time sitting. First, have you any obvious loss of fluid? ie look for a leack. Clamp each flexi pipe in turn and see if if pedal comes back, clamped cylinder, section at fault. When were shoes last adjusted?

Hi Gary - is the oil level dropping?

Hi Gary - is the oil level dropping?

Good afternoon Jack,yes the master cylinder was mt.:-|

Gary

Good afternoon Jack,yes the master cylinder was mt.:-|

 

 

Gary

Sounds like a new master then! Have a look at pastparts and consider a rebuilt unit rather than NOS. Although the American bits seem to available as new. While A**ing about. Consider the brake lines. Are they steel pipe? Adding a new master does boost pressure, the pipes might not like it. I'd recommend replace the steel with Cupro nickel, garuntted for life of vehicle, and much more mallable to get round the bits.

Sounds like a new master then! Have a look at pastparts and consider a rebuilt unit rather than NOS. Although the American bits seem to available as new. While A**ing about. Consider the brake lines. Are they steel pipe? Adding a new master does boost pressure, the pipes might not like it. I'd recommend replace the steel with Cupro nickel, garuntted for life of vehicle, and much more mallable to get round the bits.

Thanks Tony, "pastparts" are these some type of supplier ?

Brakes now working after top up and bleed,BUT I believe you are correct, replacement master cylinder is probably required.

Thanks for all the input

Gary

Gary,

I've found with several vehicles that gunge will build up in the master while the vehicle's sitting, holding the seals off the side of the cylinder. All the fluid then falls out. K9s are devils for this. Strip and clean, or sometimes even just bleed, the master and they come back right as rain. When you have the chance strip & inspect just to be sure but you may be OK.

Mind you, I know nothing about GMCs...

Past Parts are a company based in Bury St.Edmunds who specialise in refurbishing automotive parts . Very good at what they do and give good service . You should find their details elsewhere on the forum as they've been mentioned several times before by happy customers

Thanks Tony, "pastparts" are these some type of supplier ?

Brakes now working after top up and bleed,BUT I believe you are correct, replacement master cylinder is probably required.

Thanks for all the input

Gary

Pastparts are a rebuilder. They will clean the cylinder, rebore and fit with stainless steel sleeves. Modern seals and away you go. http://www.pastparts.co.uk/ First question, why did it losse fluid in the first place? If you have steel pipes take a long hard look for any sign of weepeage . as my old Mentor Howard used to say' A bu**er if they don't go, a disater if they don't stop'.

Just a little obvious thing if the fluid is gone out of the master cylinder you should see it as a leak somewhere, if the level goes down and there are no leaks in the wheel cylinders or hoses or the chassis lines then it has to be going into the hydrovac vacuum chambers, I have had this happen to me !!! then its time to check the hydrovac.

Good luck