New rabbit owner- '79 diesel rabbit with an '81 1.6L engine- and I'm having some brake trouble. Recently had my front brakes changed, pads and rotors; however, now when I brake the pedal is spongy and sometimes the pedal looses pressure and goes all the way to floor on a stop light. Any advice on what I should do? Brake fluid is good, check it often. The car does have leaks, so I think I might have a brake fluid leak in the lines, but I don't know how to go about checking it or if that's causing my current braking issues since the leaks have been there since I bought the car.
Welcome to the forum. If you know you have leaks in the brake system, you should fix those leaks because brake line systems are not supposed to leak.
If you are losing break fluid, then it's either going out a leaking line, a leaking wheel cylinder, or leaking into the brake booster. Leaking lines are somewhat easy to see as they will usually leave a wet spot on the chassis where they leak. The wheel cylinders (rear wheels) will leak into the rear drum brakes, making a mess, and if the leak isn't large enough, not much evidence of a leak. Removal of the wheel brake drums should point to the issue, or to somewhere else. If nothing is leaking anywhere that you find, then look at the booster. You could also have a shot master cylinder where the fluid is leaking around the piston, allowing the pedal to move. But, identify and fix any and all brake line leaks that you can find.
Air in your system can also give a spongy brake pedal too.
Everybody else lists their cars here - but not me.
This sounds like a master cylinder going bad and/or the brake system needs to be flushed or thoroughly bled. having old dirty brake fluid in the master cylinder can sometimes give symptoms of a bad master cylinder too. As cheap as the master cylinders are (usually $30 on line) I would replace it and flush the system. You will be amazed at the difference in braking power and consistency.
x3... for a new M/C. As the M/C goes about its work for thousands of miles/kilometres, at the extension of 'normal' piston travel, the M/C bores develop a "crud ring" (probably not the technical term, but fairly common!) of somewhat hard deposits. When the mechanic & buddy do the 'pump it up & hold' technique of bleeding the brakes, after new pads or shoes have been installed, the pump-hold-bleed sequence drives the M/C's pistons past the "crud rings", frequently tearing gashes in the rubber piston cup seals. Hence the internal M/C leaks.
Following factory recommendation to biennially flush & re-fill the entire brake hydraulic system probably minimizes the "crud ring" formation, but using a power bleeder to remove air, post-friction lining replacement, really can save some grief also.
IMHO Rabbit brake lines were prone to rust out, even inside the cab (!) if a leaky windshield rubber wasn't replaced or otherwise sealed. Good news is that the lines are relatively easy/cheap to locate-trace-replace. Best wishes for drama-free stops in the future.
Thanks for all the awesome advice everyone! I'm so happy to have a rabbit...so much fun to drive and I want to make sure I take care of it as best as I can
Kellizgar wrote:Thanks for all the awesome advice everyone! I'm so happy to have a rabbit...so much fun to drive and I want to make sure I take care of it as best as I can
I know how you feel Kellizgar, having an 85 diesel Golf (na) has really taught me a lot about diligence and well.....mechanics. This forum has been even better help than my Bentley lol, but having a Bentley doesn't hurt.
Great advice gentleman, will do with me Golf too.
My name Lee and I has a Golf. An 85 1.6L N/A Golf.
So will finally have time to work on the rabbit this weekend, and was wondering if I need to replace the master cylinder, should I get one for an 81' rabbit since my 79' has an 81' engine in it? I wasn't sure if it mattered. I'm kind of inept when it comes to cars. Will have someone who is more knowledgeable helping me, but just thought I'd ask.
you probably need an original 79 version. The brake systems were different between the German and US made cars and the early MK1s (75-79) had some different brand calipers and master cylinders. I doubt anyone would have swapped an 81 brake system along with the engine swap. Try to get a number off the existing MC before you order e replacement.
I think your lines will tell you so definately look at the routing. I think I got lucky, my 79 has the same routed lines as 82 jetta did so the hard lines mated up as well as with the goofy pressure type brake light switch.
