Brake problem, obviously..

M+10 · #1 (**permalink**) 11-07-2003, 09:10 PM

I have an 88 Spider Quad. Here's the problem. I have to pump my brakes twice to get a good solid feel. The first time I step on the brakes, they go pretty much all the way to the floor, the second time they're more firm. Any guesses as to why?

Thanks
M+10

artart · #2 (**permalink**) 11-07-2003, 09:22 PM

My guess would be master cylinder leaking by internally, if you are not losing fluid.
That should be relatively easy to detect (loss on the ground or under the car somewhere) if it's a leak outward it is going somewhere but may not make it to the ground ( line, hoses. etc. run everywhere) BUT master cylinder level has to show the loss of level unless it's sliding back and forth inside that unit.
This is all based on the premise that you haven't had any recent brake work done or refilled the MC reservour such that air could have got into the hydrallic system. If you or someone did, it could be air and require bleeding out. Then the question remains where did the fluid go, it is not consumed.

**Roadtrip** · #3 (**permalink**) 11-07-2003, 09:49 PM

Check the booster. If the rear seal goes, the brake fluid goes in there and it might not be immediately obvious.

M+10 · #4 (**permalink**) 11-08-2003, 01:33 PM

I haven't had any brake work done, and there's no noticible loss of brake fluid. The first pump just feels spongy, the second is firm. I'll poke around and see if I notice anything.

Thanks
M+10

**John M** · #5 (**permalink**) 11-08-2003, 03:52 PM

Sounds like you have lost the front seal in the master cylinder. Pumping the brake to get pedal is a bad master cylinder. You can get a rebuild kit from IAP for around $25 or a new MC for around $80 or so. As RT suggested, when you rebuild/replace the MC, check to make sure that there is absolutely no brake fluid collected in the bottom of the booster. Brake fluid in the booster will destroy the seals, ruining the booster.........and that is a $300+ part.

Best Regards,
John M

MrT · #6 (**permalink**) 09-06-2004, 09:26 PM

Well, I've dredged this up from the search. I have a similar problem. My brake pedal randomly gives me a sink to floor (or well below normal position, anyway) but picks up immediately upon second press. This has been happening for a few weeks now, with no obvious other symptoms. But today, on a hard left turn, we got the billows of white smoke that flag brake fluid in the intake. And the brake fluid reservoir had gone empty all of a sudden. No, I didn't watch the fluid level carefully, but I did have to top it off a month or two ago.

I see turkey baster suggestions, but don't know whether the suggestion is with booster mounted or dismounted. I don't want to let the fluid destroy the $$$ booster if it is OK. Is the wash-out a dismount, soap&shake, rinse, drain process? I've rebuilt brake and clutch MC's before, so no problem there. But I don't know how to drain the booster reliably.

Michael

**John M** · #7 (**permalink**) 09-06-2004, 10:18 PM

Hey Michael:

Sounds like you need to rebuild the master and clean out the booster. Pumping pedal = bad seals in the Master. Stiff pedal =$$$$ bad booster seals. I have cleaned my booster before with it mounted on the car. You can use a turkey baster as noted....or syphon it out with a tube....just don't get it in your mouth!

Then I would mix up some dawn and water. Use a spray bottle and spray all around in there. Drain that. Then H2O....and drain that. And if you really want to be particular....I suppose you could throw some compressed air at it to completely dry her out inside. Slap it all back together...and you should be good to go.

Best Regards,
John M

MrT · #8 (**permalink**) 09-06-2004, 10:49 PM

Does all this activity happen through the manifold vac port? One wouldn't try to flush the actual fluid ports, would he? And are you recommending doing these things in situ or with the booster removed and juggled in one's hands?

Michael

**John M** · #9 (**permalink**) 09-07-2004, 06:45 AM

Hey Michael:

This activity happens through the hole left once the MC is removed. And I do not remove the booster. If you wanted to go the extra mile....removing the booster and washing out will work too. Seems like you have to remove the pedal box as well.

I can't remember....been too long since I went that far.

Best Regards,
John M

MrT · #10 (**permalink**) 09-11-2004, 11:44 PM

John is correct. You can see the entire active area of the booster through the MC mounting hole. I didn't know that, and it appears that you can do all of the washing/rinsing/drying that way. Mine was brim-ful of fluid, nasty brownish red fluid that must have been there for a while.

Did you know that Beck-Arnley marketed(markets?) an over-bored master cylinder for Alfas? And on the _bottom_ of the cylinder there's a nice sticker that says "only rebuild with oversized seal kits from Beck-Arnley"? I'll bet you can guess how I found out. (Hint: you can't see it from the top and it's hard to see the bottom of a mounted MC.)

I gave up on finding oversized rebuild kits for this. In fact, I thought it so ludicrous that I didn't even ask the places I called (well, maybe once or twice; and if I knew the size of the cylinder, I proably could find it, anyway. I think Centerline lists 20 mm and 22 mm bore kits.). My local BAP-GEON store found a suitable Beck-Arnley MC in stock in a sister store, but I called them a few minutes too late for me to get to the other store and purchase it before closing. So I'll have to wait until Monday, but at least I can have it early Monday. Noon-time fix? If I had known....

Michael