Bleedin' mi brakes

[Julian H]

Hi

Tomorrow I plan to do a brake fluid change. I understand it is recommended to start from furthest away from the cylinder and work towards the closest. What is the correct sequence please?

Thanks, Julian

[Roadsport06]

I do NSR, OSR, NSF, OSF. That gives furthest to closest. I have used an easy bleed in the past but this week I used this:

https://www.amazon.co.uk/dp/B08M97BJ39?ref=ppx_pop_mob_ap_share

Worked a treat.

[Julian H]

Awesome, thanks RS06!  everything I need to know!

 

[ChrisC]

If you have two bleed nipples on you front calipers, do outside then inside. 

Assuming its a DeDion car, the biggest problem is the rears, which love to retain air because of the mounting location (i.e. not as per the host Ford Sierra), its not so much of a problem with a fluid change assuming there is no air in there already.  So don't let the reservoir run low during the bleed. 

If you suspect air in the rear calipers, get your helper to vigorously apply and release the hand brake a few times each time they press the pedal down.

   

[Wrightpayne]

My current approach is to remove (with a big syringe) all the old fluid out of the master cylinder first and refill with new. Do not touch / press the brake pedal while empty.

Logic is you're not shifting a reservoir full of old fluid through the system first. Virtually straight into pumping new fluid.

Dont get any on the paint - its good paint stripper!!

Ian

[Roadsport06]

I do as Ian does by taking out the old oil from the reservoir. It is around 70ml. I dampen a few rags too and place them around the caps of the master cylinder and the pressurised bleed kit should there be a problem and the fluid were to make a break for it. I go through 1.5 litres, you can use less than this but since I get it in 500ml bottles I get through the 3 bottles. No good having some left in an opened bottle.

[ECR]

#4 Chris

for callipers with two nipples, I always bled the outside one first but am told that the inboard one should be done first. I now shuffle backwards and forwards between them till all air is gone. I can't understand the logic of doing the inboard first....

[Graham Hutton]

I struggle with the logic of the inner front calliper nipple first too but it seems to work. I think the ideal sequence insofar as distance from master cylinder though is NSR, OSR, OSF, NSF because the pipe runs down the left hand side of the engine bay. Having said that, who cares as long as you get all the air out. When I built mine it took 3 goes with a pressure system to get all the air out including jacking the back up overnight with the pressure attached etc. Got there in the end though...

[ECR]

I'm tempted to put a tee in the bleeder line and do both together to avoid the head scratching  

[Wrightpayne]

Re 2 nipple calipers - how they are constructed means they have 4 identical drillings so they are not handed. The top holes have the bleed nipples in, the bottom holes have an external link pipe joining the two halves together. The flexi pipe is always joined to the inner half.

If you bleed the outer half (furthest) first, fluid has to pass air trapped in the inner part so there is increased risk of inducing it into the outer caliper. Purging the inner of air first means there is just fluid present to move when the front half is bled.

Thats what I think anyway - if I was filling an empty brake system I'd do inner/outer a few times and repeat after a few weeks of use.

Ian

[SM25T]

When fitting new big calipers, ensure the bleed nipples are at the top. There have been a few stories here about owners unable to get rid of the air ... then finding the nipples were fitted at the bottom !!

[SLR No.77]

Re #2,  I bought one of the pressure bleeders a couple of years ago (mine's branded as a Sealey VS820) and it's definitely far better than the Gunson Eezybleed kits which rely on pressure from an inflated tyre. Everything about it is just better quality and does the job perfectly.

Stu.

[SM25T]

Ezibleed ... from personal experience, use it dry, without brake fluid in the bottle. Any sort of leak on the hose or lid can result in a very powerful brake fluid sprayer !!

[Wrightpayne]

I managed to brim the Porsche master cylinder with the easy bleed which put me off using it. Top tip to leave the reserve top up bottle empty! 

[ECR]

Thanks for that Ian, it makes some sense….

Having thought about it, I start by assuming that there is a bubble of air sitting behind each nipple at the top of both sides of the caliper.

If I bleed the outer caliper first, that outer bubble will disappear but any fluid moving through from the inner caliper has a danger of carrying dissolved air from the bubble at the top of the inner caliper (which will still be there because the link pipe between both sides of the brake is at a low point)  which will affect the outer caliper operation.

Bleeding the inner caliper first removes the likeleyhood of dissolved air passing across

Which is pretty much what you said 

 

[JonT]

Ezibleed, but as SM25T says, I never use it with fluid in, just as a source of air pressure. It's easy enough to keep topping up the reservoir every so often.

[Julian H]

All done, thanks for the advice.

[7 wonders of the world]

Some caliper have 4 nipples - My HiSpec SVA rears do as these are not handed and have internal drillings.

Later AP castings are handed as they now had differential pistons 

When filling from new - use gravity it's that simple, naturally if your running the Sierra calipers remove and angle so the nipple is upper most

 

[OldAndrewE]

Has anyone used one of the vacuum devices that go on the bleed nipple?  Are they any good?

[ScottR400D]

I have and find it OK. You have to be careful not to loosen the nipple too much or it just sucks air in and straight out again!