Bleeding front brakes only

[Henz]

Swapping my front calipers over - can I get away with just bleeding them and leaving the rears? Fluid is new so no benefit for the rears if I don't have to.

Cheers....

[trickywoo]

It’s going to be dual circuit so front left and rear right on one and the opposite obviously.

If you clamp up the hoses well when you take off the callipers you should be ok just doing the front but it’s minimal effort to do a full bleed so you may as well.

[GreenV8S]

Yes, as long as you are able to ensure that no air can have got back as far as the circuit split. You can do that by raising the caliper before you break the circuit and keeping the hoses up until you have re-sealed and refilled it. Obviously the caliper needs to be mounted before you can bleed it.

[E-bmw]

Personally if I were breaking into the braking hydraulics I would do the lot for what it takes.

[Hammer67]

Whenever I fit new calipers I fill them up with fluid using a syringe before bolting up the pipe work.

Makes bleeding easier and quicker.

[Henz]

Cheers all, never had the pleasure of bleeding brakes before and reliant on the wifey for pumping the pedal, so was hoping to limit her requirement/whinging. Might invest in a pressure kit and do the lot.

Any recommendations? Sealey VS280 has good reviews and seen a good video tutorial, whilst Gunson eezibleed 1/2 the price but seems to do the job.

The easier and more idiot-proof the better.

Hammer67 said:

Whenever I fit new calipers I fill them up with fluid using a syringe before bolting up the pipe work.

Makes bleeding easier and quicker.

That sounds a very handy tip cheers, I like easier and quicker!

[trickywoo]

I’ve got a vs820. Brilliant bit of kit.

[NMNeil]

Old school way of bleeding even the most stubborn brakes.
Have an assistant pump hell out of the brake pedal until it goes solid and then get them to stop, but keep the pressure on the pedal.
With a length of clear plastic tube over the nipple to catch the fluid and watch for air bubbles, open the bleed nipple as much as you can until the brake pedal is on the floor, and tell the assistant to keep it there.Tighten up the nipple, top up fluid, and if needed, do it again, then move to the next wheel.
By getting the assistant to put lots of pressure on the fluid, when you open the nipple, all the crap and air are forced out under pressure. This even shifts those stubborn air bubbles that are clinging to the inside of the brake lines.

[tr7v8]

NMNeil said:

Old school way of bleeding even the most stubborn brakes.
Have an assistant pump hell out of the brake pedal until it goes solid and then get them to stop, but keep the pressure on the pedal.
With a length of clear plastic tube over the nipple to catch the fluid and watch for air bubbles, open the bleed nipple as much as you can until the brake pedal is on the floor, and tell the assistant to keep it there.Tighten up the nipple, top up fluid, and if needed, do it again, then move to the next wheel.
By getting the assistant to put lots of pressure on the fluid, when you open the nipple, all the crap and air are forced out under pressure. This even shifts those stubborn air bubbles that are clinging to the inside of the brake lines.

Issue with this is full stroke on the old master cylinder can destroy the seals as they're travelling a bit of the bore they never normally travel into.

[PositronicRay]

A pressure bleeder makes sense, particularly with abs.

Gunson works fine for occasional use.

[Henz]

The wife's patience is minimal in these matters so pressure bleeder it is!

As my current fluid is not that old, concerned it might not be that obvious when the new is coming through. I assume if I can use the same stuff as currently used then all good to stop just when no more bubbles?

[GreenV8S]

Henz said:

The wife's patience is minimal in these matters so pressure bleeder it is!

Having two people working together who know what they're doing makes this extremely quick and effective, but for inexperienced people I think that is an awkward way to do it. However, there's a simple way to do this solo which I find very effective and better than a pressure bleeder. I take a clear hose from the bleed nipple up to a jar placed where the driver can see it. This puts the nipple/hose connection under a slight pressure at all times so there is no tendency to pull in air. You just pump the pedal until the bubbles stop. Sometimes it can be difficult to chase out the last bubbles and in that case instead of dumping fresh fluid I will put the hose into the reservoir so the fluid recirculates. I prefer this to pressure bleeding because there's no worry about spraying brake fluid around if the pressure seal fails, and no worry about running out of fluid if you take too long.

[NMNeil]

tr7v8 said:

Issue with this is full stroke on the old master cylinder can destroy the seals as they're travelling a bit of the bore they never normally travel into.

If it's that old and worn it's time for a new one then

[Jakg]

E-bmw said:

Personally if I were breaking into the braking hydraulics I would do the lot for what it takes.

I'd do it all - every time I work on brake hydraulics, when I drive the car after I'm always convinced I've got air in somewhere as it always feels "wrong" for a bit.

If I knew I'd only done half a job I'd end up bleeding them all afterwards anyway.

Henz said:

Cheers all, never had the pleasure of bleeding brakes before and reliant on the wifey for pumping the pedal, so was hoping to limit her requirement/whinging. Might invest in a pressure kit and do the lot.

Any recommendations? Sealey VS280 has good reviews and seen a good video tutorial, whilst Gunson eezibleed 1/2 the price but seems to do the job.

Henz said:

The wife's patience is minimal in these matters so pressure bleeder it is!

I have exactly the same situation (re wife).

I bought a Eezibleed and it worked for a bit - bit of a faff to get a wheel pressurised.
Unfortunately, nothing really seals together that well and after a while it didn't hold pressure properly.
I bought another and it went the same way.

I contemplate asking for some help but thought it was easier just to buy more tools...

I bought the Sealey bleeder - half the reviews said it was fantastic, half said it leaked. Mine turned up and leaked - until I found a tip online to put silicone grease around the cap and it was fine since and very easy to use.

[Henz]

Yeah cheers, come round to that way of thinking.

Have got a Sealey now and good hint if it suffers the leak. I'm getting in to trackdays so it's something I'll want to do myself rather than paying out... should be a good investment!