# Brake fluid plastic reservoir fix?



## Tozguy (Mar 9, 2021)

Does anyone know of a glue that could be used to fix a cracked plastic brake fluid reservoir?
Rest assured the reservoir is not going on a car or truck. It is for a brake fluid vacuum tool that I am cobbling together.  
Welding the plastic is my plan B but I would really like to find a glue that would resist brake fluid.


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## ErichKeane (Mar 9, 2021)

Loctite plastics mentions fuels, so presumably brake fluid would work too: https://www.amazon.com/Loctite-Plastic-0-85-Fluid-Syringe-1363118/dp/B0044FBB8C


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## benmychree (Mar 9, 2021)

Shoe Goo (vinyl cement) might work, clean with acetone first.


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## Mitch Alsup (Mar 9, 2021)

I am going to guess:: no :: brake fluid is nasty stuff.


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## RJSakowski (Mar 9, 2021)

I would expect the reservoir to be made of something like polypropylene in which case you would need to weld it.


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## randyjaco (Mar 9, 2021)

It is probably polyethylene. It will most likely will have to be welded.


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## Tozguy (Mar 9, 2021)

It seems like finding a glue for this would be a long shot. Going in I realized that brake fluid is really nasty stuff and any plastic that could be glued successfully would not likely resist going soft (or hard) with prolonged exposure to brake fluid.
The glue that Erich mentions in post 2 looks interesting however. It is new to me and I plan to try some just for the experience.
Thanks for your thoughts everybody.


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## RJSakowski (Mar 9, 2021)

I suppose you could try Flex Tape. If it will hold a boat together, well....


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## pdentrem (Mar 9, 2021)

Back in the day, I used plain old glass jar that has a rubber sealing lid. Solder a couple short tubes for the hoses through the lid. Even used it to remove the oil from the Paxton supercharger with one hose hooked to a vacuum source on the engine. Naturally the drive belt was removed while changing the oil!
Pierre


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## Tozguy (Mar 10, 2021)

Pierre, thats what I have been using all these years. But these days I need a project to keep me busy


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## brino (Mar 10, 2021)

For either adhesive or welding you will have to clean the crack out very well. I agree with acetone for that.

I learned a bunch with my adventure into plastic welding a fuel tank.
It wasn't as difficult as I thought it would be.
There are some links in that thread to tools and filler materials.

Look for markings on the part to identify the plastic.
Do a bit of research and practice.

You can do it!
-brino


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## Tozguy (Mar 10, 2021)

There are no markings on the canister to identify the plastic; it only has Nissan and a PN on it.
Over the years I have welded up a few plastic items using a soldering iron; the most successful being ABS motorcycle fairings. From my limited experience and from machining this particular canister my guess is PP.

Last night I tested some regular yellow ABS plumbers cement and also some epoxy cement supposed to be resistant to gasoline, etc. on a piece of PP. The epoxy did not stick well and softened up terribly after soaking overnight in brake fluid. Surprisingly the yellow ABS glue did not soften at all in the brake fluid and stuck pretty well. I had used the primer prescribed for cleaning plastic plumbing before applying the yellow glue.


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## Flyinfool (Mar 10, 2021)

That is surprising that the ABS glue seemed to hold up to the brake fluid, since brake fluid will have ABS for lunch. But it does take a while for the ABS to suddenly disappear.
Even calling the glue manufactures for technical assistance. There is no adhesive made that will effectively bond PP. there are some that will kind of get a grip IF the surfaces are roughened up a LOT so that the glue is able to make a mechanical bond to the irregular surface. A container for brake fluid is intentionally made of a very chemical resistant material, so it is hard to find a chemical that can etch into it to make a solid bond.

Plastic welding will be the only permanent fix.


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## AGCB97 (Mar 10, 2021)

You could probably use DOT 5 brake fluid. It is silicone based and doesn't have the same problems as regular DOT 3.
Aaron


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## Flyinfool (Mar 10, 2021)

DOT 5 is also NOT compatible with the rubber components used in a DOT 3 system.


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## Nogoingback (Mar 10, 2021)

For all the effort needed to figure this problem out, you might consider trotting down to a wrecking
yard and buying a brake fluid reservoir: probably cost almost nothing.


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## Packard V8 (Mar 10, 2021)

The translucent poly plastic used in brake, coolant, washer reservoirs won't take any glue I've tried.  As mentioned some have some success with welding.  However, some variants degrade so with time and sunlight that they go junk.

jack vines


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## TCSmith (Mar 10, 2021)

I assume this will be used from brake bleeding.  Many years ago I transitioned to pressure bleeding through the master cylinder.  In my opinion it is the way to go.  I have seen and had issues with vacuum bleeding.  
If I was looking to make something for brake bleeding it would be a pressure vessel that could hold 1-2 qts of brake fluid and hold @ 60 psi.  (most systems don't require the higher pressure but some do.)


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## Tozguy (Mar 10, 2021)

The container that I am using is a charcoal canister for gas vapour recycling from a Nissan pickup. It has been gutted to remove the carbon media and filters. My plan for it is to make a vacuum canister for bleeding brake fluid and solve any issues that might arise along the way to make it work. The container itself is proven proven resistant to brake fluid. Doin it just for the challenge. If it ends up in the garbage can so be it.


TCSmith said:


> Many years ago I transitioned to pressure bleeding through the master cylinder. In my opinion it is the way to go. I have seen and had issues with vacuum bleeding.


Would you please elaborate TC that sounds complicated.
The reason I want the vacuum approach is so I can do the job alone without help. Am curious as to the issues you had.


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## Tozguy (Mar 10, 2021)

RJSakowski said:


> I suppose you could try Flex Tape. If it will hold a boat together, well....


Plan A is still on the front burner but......
Flex tape has been bumped up to plan B.
Welding is now plan C.


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## RJSakowski (Mar 10, 2021)

Tozguy said:


> Plan A is still on the front burner but......
> Flex tape has been bumped up to plan B.
> Welding is now plan C.


I hope you didn't take me seriously about the Flex Tape.  Considering the nature of the repair, I think welding is the only option.  I don't expect to find any adhesive that would bond to the plastic well enough to seal a crack.


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## aliva (Mar 10, 2021)

Just a shot, but try some fiber glass matting


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## Tozguy (Mar 10, 2021)

No worries RJ just funnin along with you.
It is clear to me that any common glue will not give a structurally sound repair on HDPE or PP.
I just got back from my neighbour's garage. He is a retired mechanic who is heavy into restoring old cars, bikes, etc. 
When I asked him how he bleeds brake fluid he said he uses gravity and patience. That sounds like it might be my next plan B.


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## markba633csi (Mar 10, 2021)

I gave up on vacuum and pressure bleeding gadgets on my Alfa Romeo.  I just use a quart Gatorade bottle 1/3 full of brake fluid with tubing from bleed screw running thru the lid to the bottom.  Crack the bleed screw, hop in the car and give 10 to 12 quick stabs of the pedal, hop out and close the bleed screw. Keep master reservoir full.  Repeat as required then move to the next wheel.  Quick and easy, and doesn't require two people.
-Mark


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## nnam (Mar 10, 2021)

Using a one way valve inline with a tube can take place of a person.


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## Tozguy (Mar 10, 2021)

I must be missing something. With someone stepping on the brake pedal I open the bleed nipple on a caliper and release the pressure. Then before I say to release the brake pedal I have to close the bleed nipple or air gets sucked in along the threads of the nipple.
I don't see how a submerged tube as Mark mentioned or an inline check valve would prevent air from leaking up the loose nipple threads. Please clue me in.
With the constant vacuum system I have used there were air bubbles getting into the flow of fluid coming out of the caliper. At least the air bubbles were not getting into the caliper but it was clear where the air was coming from.


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## nnam (Mar 10, 2021)

You are right about the pedal and release and air going back in part.  The check valve is installed so you can push air and fluid out, but not allowing them back in, so the orientation needs to be correct.

We can make one easy with a lathe, a tube and a spring and bearing ball.  Or just buy it


			https://www.amazon.com/dp/B08H4ZJBJM/ref=cm_sw_r_cp_apa_fabc_MSJYCW3D4VTEHWY5G7H6


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## Flyinfool (Mar 10, 2021)

I have put Speed Bleeders on a bunch of vehicles. It is a check valve that replaces the bleeder. When you press the peddle the check valve allows fluid to pass just like if someone was there with a wrench, when you let off the peddle the check valve closes and prevents air from getting sucked back in. The check valve has a sealant on the threads to prevent air leaking in around them. WHen you are done just tighten like a normal bleeder.


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## ErichKeane (Mar 10, 2021)

Flyinfool said:


> I have put Speed Bleeders on a bunch of vehicles. It is a check valve that replaces the bleeder. When you press the peddle the check valve allows fluid to pass just like if someone was there with a wrench, when you let off the peddle the check valve closes and prevents air from getting sucked back in. The check valve has a sealant on the threads to prevent air leaking in around them. WHen you are done just tighten like a normal bleeder.


I just did a set of speedbleeders in my sports car.  it has a routing that must trap air, because I can find air in it all day. Additionally, it is super nice I could do it on my own as well!  Having someone pump the brakes is a pain.


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## Tozguy (Mar 11, 2021)

Speedbleeders, now I get it!
I never heard of them (or I forgot that I knew about them). Thanks folks.


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## nnam (Mar 11, 2021)

I reread your comment and I realized that I didn't answer it.  I never have problems with air going in the thread.  I just crack it enough to allow fluid and air to come out.   Maybe some oil tries to get out that way and seal it up also.


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## TCSmith (Mar 11, 2021)

Tozguy said:


> The container that I am using is a charcoal canister for gas vapour recycling from a Nissan pickup. It has been gutted to remove the carbon media and filters. My plan for it is to make a vacuum canister for bleeding brake fluid and solve any issues that might arise along the way to make it work. The container itself is proven proven resistant to brake fluid. Doin it just for the challenge. If it ends up in the garbage can so be it.
> 
> Would you please elaborate TC that sounds complicated.
> The reason I want the vacuum approach is so I can do the job alone without help. Am curious as to the issues you had.


So I have had and have seen vacuum style bleeds introduce air into the brake system.  I never looked into why or where, it was not effective which was enough for me to look at different solutions. 
Being able to bleed the majority of the air out of a brake system with no assistant was the need.  Some modern brake systems, specifically the master cylinder have pistons in them that have a 50 PSI or so cracking pressure and they will not allow fluid flow until that pressure is reached.  Vacuum bleeders will not operate this piston.  Some pressure bleeders don't have enough pressure capability either.  
All this being said at the shop my policy is that the brakes are bleed using the pressure bleeder, then bled with an assistant for the final bleed using the brake pedal.  Then the vehicles are cleaned of all fluid residue and pressure tested with the engine running to verify no leaks.


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## nnam (Mar 11, 2021)

It's good to have a way to see if there are still bubbles and color of the fluid.  Other than that, the spongy feeling of the pedal can tell how much air is in there.

Good point about vacuum can't provide enough force to move fluid under piston.   I bought to toss it aside 

Some leaks can be from connections, that are good at sealing fluid in, but not enough for preventing air to come in.  System with very slow leak can also have this issue


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## Shotgun (Mar 11, 2021)

I have a one-gallon garden sprayer that I use to fill hydraulic lines.  

- Remove the reservoir cover and completely drain the lines you want to fill in order to get rid of any existing bubbles . 
- Cut the nozzle off the sprayer.  The wand/hose should now be a tight fit on the brake fitting.  
- Pump up the sprayer.
- Push the wand onto the fitting and squeeze the trigger.  
- Keep an eye on the reservoir, as it will fill up quick.



			https://www.tractorsupply.com/tsc/product/groundwork-groundwork-pump-sprayer-1-gal-capacity-24001-1388527?cm_mmc=feed-_-BingShopping-_-Product-_-1388527&utm_source=bing&utm_medium=cpc&utm_campaign=Shopping%20-%20All%20Products&utm_term=4585375807245420&utm_content=All%20Products


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## TCSmith (Mar 12, 2021)

Shotgun said:


> I have a one-gallon garden sprayer that I use to fill hydraulic lines.
> 
> - Remove the reservoir cover and completely drain the lines you want to fill in order to get rid of any existing bubbles .
> - Cut the nozzle off the sprayer.  The wand/hose should now be a tight fit on the brake fitting.
> ...


I like to use pump sprayers for pressure vessels also.
I would not try to force brake fluid from the bleeder toward the master.  
If making a pressure bleeder you would want to purchase or make adapters for the master that replace the cap during bleeding.


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