Sinking Brake pedal

morgan · Post by **morgan** » Sun Jul 22, 07 8:31 pm

One to throw out see if anyone has an idea...

Noticed when sitting in traffic the other day my brake pedal seemed to slowly sink (like over the course of a minute) towards the floor.
Car doesnt actually start to creep, but is is quite odd.

Take foot off pedal again, and system 'recharges' before the slow sink starts again.

Car stops fine, drives fine, and crucially does not seem to be leaking any fluid. (rear reservoir was low, but I topped it and it stayed there.)
Car is front factory disks, drums at rear. Given no leaks, and given that it does stop (I mean it'll lock the wheels quite happily) it doesnt feel like a leak. Nothing running down the tyres or on the floor either.

Any ideas ? Is is possible that is is getting arund the piston in the master cylinder or something ? If so - how would it get back again ? Its a bit odd....

Ideas ? New master cylinder ? Seals gone ? Was gonna do it in the winter anyway...

Kev · Post by **Kev** » Sun Jul 22, 07 8:47 pm

New master cylinder required! That is the classic sign of knackerage! Sooner rather than later! It's the seals on the pistons letting by.

Derek · Post by **Derek** » Sun Jul 22, 07 8:48 pm

morgan · Post by **morgan** » Sun Jul 22, 07 8:56 pm

Thanks chaps.

Wil ! (Neil) - another bit to price up please (sigh!)

Anonymous · Post by **Anonymous** » Mon Jul 23, 07 7:58 am

Morgan

no problem, can you email me the details on the car, year and what front brakes disc or drum is all I need

I have a few mastercylinders in stock

Anonymous · Post by **Anonymous** » Mon Jul 23, 07 12:38 pm

Wil wrote:Morgan

no problem, can you email me the details on the car, year and what front brakes disc or drum is all I need

I have a few mastercylinders in stock

Hi Neil, i need one for a 69 satellite, power drums. Double res with 2 lines out.
If you can bring one to the nats ill pick it up there if you have one.
Thanks Mo.

morgan · Post by **morgan** » Tue Jul 24, 07 8:37 am

Quick update for all you sportsfans out there...

Seems that (wouldnt you know it) my car has an awkward option on it. Factory discs mean that I cannot easily get a new master cylinder.

Neil is going to try and get one, but it looks like rebuild kit could be the only option. Looking in the 'Yearone' catalogue it seems to list every type of brake cylinder EXCEPT 68 charger with discs.

Nearest I can see is -NG90109 "1967-1969 B-body Hemi models with power disc brakes and 1970 B and E body hemi models with power disc brakes"

Now - whilst my lowly 318 has no delusions of grandeur - is it possible that the factory discs are the same as the hemi models and therefore the master cylinder rebuild kit is the same ?

Any ideas ?

Pete · Post by **Pete** » Tue Jul 24, 07 8:39 am

All hemi cars had the brake pipes exiting on the opposite side of the MC - be careful.

morgan · Post by **morgan** » Tue Jul 24, 07 8:50 am

Bummer. Mine exit on engine side. Thanks Pete... will investigate.

steveo · Post by **steveo** » Tue Jul 24, 07 8:54 am

hi morgan , if nothing has been changed on yours over the years, it should be the same set up as the factory disc 67-69 b-body Hemi cars . brake pipes may be able to reach the other side , as they are coil up

Anonymous · Post by **Anonymous** » Tue Jul 24, 07 8:54 am

morgan wrote:Bummer. Mine exit on engine side. Thanks Pete... will investigate.

Pete / Morgan,

I dont understand what is being suggested here. Am I right in understanding that the b. pipes on hemi cars ALWAYS exited the MC towards the fender? Mine did on my 440

Pete · Post by **Pete** » Tue Jul 24, 07 8:55 am

Rebuid kit will probably be the same.

I have run a later master cylinder on those type of brakes with no problems.

morgan · Post by **morgan** » Tue Jul 24, 07 9:07 am

steveo - You are right - pipes are 'coiled' , so should reach round to the fender-side if needed. As far as I know this car is all original. (Too original - thats why it all needs overhauling

)

This is what is on there.

steveo · Post by **steveo** » Tue Jul 24, 07 11:11 am

just doubled checked , all 68 chargers with factory disc set up , had the same master cylinder , as the hemi cars , out lets on the engine side ,same as yours .

Anonymous · Post by **Anonymous** » Tue Jul 24, 07 11:19 am

steveo wrote:just doubled checked , all 68 chargers with factory disc set up , had the same master cylinder , as the hemi cars , out lets on the engine side ,same as yours .

That changed for 70.

Checked up on a site and it shows disc braked big bklock cars with pipes exiting towards fender. Odd change, doesnt seem to be a point to it?