Scott Peterson

I'm replacing the mc and I cleaned out the Brake Fluid Reservoir as best I could, I used all the tricks I could find on RL and it's still got gunk and looks plugged on one side.




I used simple green, brake cleaner, choke cleaner, I thought maybe it's rust in there and I even tried some CLR rust and lime remover in it and let it sit. It's still got the screen plugged.
Do I just leave it or try cutting the top off and gluing it back together. It looks like when it was made it was glued or thermally bonded some how so I should be able to do the same thing. What do you guys think. I'll take any suggestions.
Thanks

dr bob

Rubbing alcohol is the most aggressive solvent I'll use in a brake fluid reservoir. If I had deposits as you show and they didn't come out with what you've used, my next step would be Simple Green in the ultrasonic cleaner.

There's no good way to glue the reservoir back together if you cut it apart. Short of ultrasonic or RF welding anyway. No glue you'll use will stand up to extended brake fluid exposure.

The reservoirs are used on other cars that use similar ATE master cylinders, so they aren't quite at outrageous on the Bargain-to-exorbitant 928 cost scale. You can buy new if needed, and for sure should replace the grommets when reassembling even if it's the old one.

Stan recommends using Dow DC111 on the inside and outside of those grommets, so that the corrosion devils can be held at bay. Any brake fluid that seeps is a moisture magnet, plus it doesn't evaporate. Add some engine-bay heat and you have a recipe for rust.

FredR

Knowing the way plastics degrade in the engine bay and the cost of master cylinders I would have thought a new reservoir was a no brainer never mind trying to clean it up.

Mark Anderson

new are over $400 so....

monkez

If you have access to an ultrasonic cleaner, try that. Theoretically, you won't really need to use anything corrosive, though I'm a fan of using a 3:1 mixture of simple green when i clean parts. I've used mine to clean *lots* of my parts that were just plain stubborn...

Mrmerlin

Well if you can blow through each hole then it will flow fluid . if not then,
Call mark at 928 INTL see if they have a used tank and put it on,
make sure to use the DC 111 on the grommets or your new MC will soon be rusting at the inlet ports

FredR

Make no wonder the OP wants to clean it - that pricing is utterly disgraceful for something that does little more than hold a thimble full of brake fluid at zero pressure. Fully appreciate it is not your fault but it just leaves me wondering what other cars use the same product under a different guise or are similar enough to do the job. I cannot believe ATE go out of their way to make every reservoir different any more than they make every master cylinder different albeit I would not be too surprised if Porsche has a custom specification but the reservoir?.

I did some research on master cylinders some time ago but found it difficult to fully break the ATE parts code. I got the impression that for the master cylinder there is a generic coding for the general series and some digits for specific models- whether there are any specific technical differences who knows. Maybe one of you bright parts chaps can to do that sooner rather than later or get Mr Wun Hung Lo to make some.

GregBBRD

Brake fluid and all the residue it leaves behind is water soluble. Choke cleaner is not.

I clean all the ones I do in my Ultrasonic cleaner, followed by an alcohol rinse.

Scott Peterson

An hour in the ultrasonic help a bit. It made it so that now I can see through it. It's no longer plugged to my eye. It's still a little dark but cleaner. I'm just going to put it back in.

Here is the weird thing , the reservoir has a set of "min" & "max" lines on it that are under the fender on the back side and on the side towards the booster, on two sides that are completely unreadable and useless. They must be there because this reservoir is used on other vehicles.In all reality we just need a Reservoir that has the hole spacing to fit the mc and is just not any taller. There is plenty of room for a wider reservoir just not taller and hopefully not cost 400 bucks.

Scott

Mrmerlin

the only other thing to consider is that this tank also has a port for the clutch system,

I would guess some of the other tanks might not have this and thus its a specific need.
As Greg points out the carb cleaner shouldnt be used to clean the tank.

Hey_Allen

One possibility (that I will be checking shortly) is the mk4 (early 2000s) VW brake reservoir.
The clutch supply hose isn't arranged quite like the 928 reservoir, but they are equipped with one.

I have a set of 928 reservoir grommets on the way, as I'm planning to break down the brake and clutch system for refresh, before hopefully putting the car back on the road this summer.

Mrmerlin

new master comes with new grommets,
take them out, put the DC 111 on the bore and grommet then fit the grommet

NOTE dont turn the MC over with the grommets removed as the inlets have flat shields in them

jpitman2

My reservoir has a MIN mark (with a flat sort of ^ ) on all 4 faces. Max mark only on front and rear. Would flushing with isopropyl alcohol be safe?
thanks
jp 83 Euro S AT 57k

Zirconocene

Isopropyl alcohol will be safe, just make sure to let it all flash off before refilling the reservoir with fluid, as residuals in the system will affect viscosity and boiling point (even if only to a negligible degree). Blowing air through the reservoir will help to evaporate any residuals.

Cheers