LUVTruck.com

Does anyone know what the gasket is made out of that is between the drum and the other part on the master cylinder? I have a 79' LUV that leaks brake fluid there. Does anyone know where I could get this gasket?

If by drum you mean the power brake booster, there is no need for a gasket there. If you are leaking brake fluid out between the booster and master cylinder, then you have a bad master cylinder.
On a master cylinder the fluid is contained inside of itself. The booster is dry. It's only contains vacuum ,(when the eng. is running), to make power to help apply the brakes.

_________________
OK, I'm over it. Where's the beer?

I have a diagram that shows a gasket there, if there is a leak wouldn't the vacumm not do its job and when you compress the brakes wouldn't it leak there? It's not leaking from the Booster but out between them. Where could I get another master cylinder?

autozone has msater clynder their are about $20 with a $20 core charge they have a lifetime warrenty on theem they will probly have to order theem it took theem 1 day to grt theem here for me i used theem on both of my luvs trucks and they work great the boster is seiled so it wont leak the easeyest way to check if the boster is working right is to have the truck off and depress the break peddle and feel how the peddle does not go down that far and its realy stiff now let off and strat up the truck now depress the break once more it sould gown easer and deeper

I got one from Pep Boys once.

_________________
OK, I'm over it. Where's the beer?

I got some from a gal named Mary Lou twice back when I was in high school.

Yeah ive heard stories about her. I got told she invented the term airtight.




From what youve said your a bit of a novice. My adivce is that with brakes you replace it with a new part. Its not worth messing about with brake stuff just to save a few $$$. I also advise that if your not 150% sure on what your doing with brakes get someone who knows there stuff to help you.

So grab yourself a new master cyl and find someone who knos brakes to give you a hand to fit it.

Hows your pedal feel??? Soft? Hard? Spongy??



Cheers, Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

Are we still talking about Mary Lou?

yeah, usually leaky brake fluid is a sign of a bad master cylinder. Its like when a water pump starts leaking out of the weep hole, it means its shot.

Go with a new one. Even if the truck was only a few years old, and not almost 30, it is easier/better to just replace it with new instead of trying fix the old stuff.

_________________
No LUV anymore, but still in the GM truck family. Running a lifted 2002 Silverado Z-71!

Thank you for your help. The brake pedal usually depresses all the way and then gets stiff and brakes correctly when pressing it a second time. I have no idea who Mary Lou is. Would I need to bleed all the lines after installing a new master cylinder. I'm a novice at fixing my truck in certain areas I haven't had a problem with, lol. It was originally my dad's and I've owned it for about 10 years.

Yes you will need to bleed the brakes. If you undo any part of the brake system that contains fluid it needs bleeding.



If you have to press twice (pump the brakes) to get a pedal that sounds like youve got air in the system.
Either youve undone something and not bled them.
Ran the reservior dry and air has got in.
Or you have a bad seal somewhere that letting fluid out and air back past.


Actually i thought of another, youve got an old car with drum brakes that was made in england. They had woefull brakes for keeping a pedal.


Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.

Thank you for the great information.

Count your blessings. Time has not been kind to good old Mary Lou...lol

But seriously...if you get a new master cylinder, make sure you bench bleed it before you install it to avoid installing it dry which will run the risk of destroying the seals in it.

Then you need to inspect your brakes at each wheel to see if they are still serviceable or leaking. Assuming they are all OK - then start at the wheel farthest from the master cylinder and work your way to it one wheel at a time. If you decide to replace your brakes - only take one side apart at a time so you can use the other side as a guide to see how to out it all back together properly.

Bleed each wheel untill no more aircomes out and you get nothing but straight fluid and checkyour fluid frequently so thatyour master cylinder never runs out, and make sure youremember to put the lid back on the master cylinder after you fill it each time.

Read the brakes section in your manual thoroughly before you get started and keep it handy while you are working on your truck and you shouldn't have any trouble.

Good luck!

Also mine is a 79 luv and it has drum brakes front and rear.

They are old worn out and in need of a complete overhaul.
I am replacing the fronts with discs from a later pup.


On vheicles with drum brakes adjustment greatly affects brake performance. Being a luv, they are a well designed setup and self adjust well as long as everything is put together correctly.

Drum brakes are also more prone to leaking and due to their design when worn or aged they can let air back into the system easier.


Replacing the lot is not overly expensive. Wheel cyls are under $20 each. Change over brake shoes are under $40 a set of 4. The master cyl is the most expensive part but you only need one.

While your at it look at the rubber flex hoses. They are approaching their 30th birthday and probably due for replcament.
Hoses arent real cheap but there are only 3.

Cheers, Bob.

_________________
Current project, 1979 KB Isuzu Ute.

Daily driver, '86 Rodeo Spacecab.
Chasing parts for Isuzu Impulse.