Jump to content

How to…. Drain and flush hydraulic brake system


Recommended Posts

As the title says.

Am intending to drain and flush an hydraulic system that has had the wrong fluid put in it.   Mixed Dot 5.1 with Dot 5

New seal kits in all components obviously once the system is drained but how to ensure all the fluid is cleaned through.   Pump brake cleaner liquid through it perhaps?

Where to start draining from?

Refill and bleeding will be after the system is drained and cleaned through.

How good are the pressure bleeder kits?   The one I had years ago blew brake fluid all over my underbonnet area.  
Any recommendations for which kit to use.?  

Edited by BlueTR3A-5EKT
Link to post
Share on other sites
19 minutes ago, BlueTR3A-5EKT said:

As the title says.

Am intending to drain and flush an hydraulic system that has had the wrong fluid put in it.   Mixed Dot 5.1 with Dot 5

New seal kits in all components obviously once the system is drained but how to ensure all the fluid is cleaned through.   Pump brake cleaner liquid through it perhaps?

Where to start draining from?

Refill and bleeding will be after the system is drained and cleaned through.

How good are the pressure bleeder kits?   The one I had years ago blew brake fluid all over my underbonnet area.  
Any recommendations for which kit to use.?  

I have an Ezi-bleed kit and like you, the last time I used it I sprayed fluid all over the under bonnet area. 
Rgds Ian

Link to post
Share on other sites

The better kits don't blow out, they suck into a large receptacle...such as Ian's suggested ezibleed which is also the one I use.

I flushed out the Scimitar system when rebuilding it...I would suggest starting from the furthest point from the master cylinder and remember to keep topping up!

Link to post
Share on other sites

Flush the system through before you take calliper's and wheel cylinders off to change seals. Then once you finished flushing then blow the system through with an air line. 
Regards bleeding I have had the same results as you with the pressure bleeders.

Now use a vacuum bleeder with reasonable results

Edited by Chris Hale
Link to post
Share on other sites

Thinking about it logically, if you are going to replace all the seals it means that you will have to take out all the pistons in the MC, slave cylinders and calipers.

Easy enough to decontaminate them while they are on the bench.

Then all that is left are the pipes and cylinder bodies.

Compressed air, and block up the cylinders one at a time until each one is free of fluid.

Then maybe blow through some liquid to finish off the cleaning process. Maybe meths.

My dad used to run a pub when I was a kid. (Old school stuff with "Beer engines". ) He used to put a small plug of sponge in the pipes and pump it from the barrel end to the pump end, then dismantle the pump and take it out. Maybe you could do something similar.

 

Link to post
Share on other sites
53 minutes ago, BlueTR3A-5EKT said:

Did you clean/flush through with brake cleaner?   I have a gallon to hand.

 

I used methylated spirit to flush the system.

You can get a big tin of it from screwfix for not very much and then once flushed it can be used to light your bonfire 

George 

Link to post
Share on other sites

Alec always used to recommend Meths to flush through as well. The vacuum bleed is a better bet as your not going to blast it everywhere then.

Stuart.

Link to post
Share on other sites

Used Eazibleed quite a few times now with no issues just use it at 4-5 psi not the 10 in the info leaflets and wrap a few rags over it just in case.

Andy

Edited by PodOne
need to revise the difference between Bar and psi!
Link to post
Share on other sites
1 hour ago, PodOne said:

Used Eazibleed quite a few times now with no issues just use it at 4-5 bar not the 10 in the info leaflets and wrap a few rags over it just in case.

Andy

I suspect you don't mean 4 - 5 Bar, that would be circa 60 - 70 psi

Rgds Ian

Link to post
Share on other sites

I use Eazibleed, I have had an issue with leaks, but my kit came with a number of various reservoir lid adaptors……only one was correct, but at-least one other appeared to fit…….it didn’t when pressurised :-(.
 The one that fits doesn’t leak and works well although I have clothes everywhere just in case!

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.