DIY universal brake bleeding adaptor

[Pugglt Auld Jock]

I recently posted about a front caliper problem on my daughter-in-law's Jazz (caliper woes) which was cured by fitting a new N/S/F caliper. Then, of course, it had to be bled out to eliminate the air from the system. I would normally do this with the help of my Gunson Eezibleed but the kit doesn't include a cap which fits the master cylinder reservoir, so Mrs Jock assisted with the pedal pumping duties and we did it the "old fashioned" way. I am always worried about damage to the master cylinder seals on an old car like this when you bleed by this method (I put a wooden block under the pedal so it can't be pushed all the way to the floor). Luckily the bleeding seems to have been successful but the fluid looked a bit past it's best and I've got rear disks and pads still to do - O/S/F caliper is a little suspect so I'm going to pop the piston out and check it over at the same time. When it's all back together again it would be criminal not to do a complete fluid flush but there's the problem of the master cylinder.

I was going to just buy a universal cap. There are a number of universal master cylinder caps on the market. Indeed Gunson do one. I started reading the reviews and there are quite a number of instances of people finding it impossible to effect a seal due to these caps not being substantial enough to resist distorting when done up tightly enough and the last thing you need is a nicely atomized spray of brake fluid - which you probably won't know is happening (until it's way to late) because you are going to be down at a wheel actually doing the bleeding.

So, thought I'd have a go at making one. I've actually been thinking of doing this since I realized a nice dished aluminium "washer thingy", which had been part of the transport securing fittings on an old washing machine, would be a good starting point. I have a box of various fittings which I rifled through and between that and some brake stuff I came up with this:





The hooks are actually a M6 turnbuckle cut in half and the big seal is a circle cut from an old inner tube. You have to remember that because it was a turnbuckle one of the screws tightens clockwise and the other anticlockwise - I can live with that. Talking about "life" I'm not too sure how well the rubber seal will fare. The brake fluid is going to attack it but I'm banking on it not giving in during a quick bleeding operation. If it proves to be problematic I've heard of a type of rubber sheeting used in roofing which will resist it - I've a friend who's a roofer!

The proof of the "pudding" is always in the "eating" though isn't it? So having cobbled it all together it was time to pressure test it. I had to cut the original end off and join it to the pressure vessel:



It's all a bit Heath Robinson and I wouldn't have been surprised if it leaked all over the place, but I didn't want to spend much money in case it didn't work - I was particularly concerned over whether a seal could be achieved on to the master cylinder. So, how to pressure test it? Just by chance I had a curry mix jar in the glass recycling which had a neck size similar to the Honda's! So I coupled it all up and hauled Twinkle's spare tyre out to use in the time honoured fashion:



I started off at 5psi and worked up in 5psi increments to about 35psi checking with soapy water for leaks every time.



I was a little worried about the jar maybe blowing up so I kept it covered with an old sheet each time I made the new connection but it was fine. (wonder how much it could take?) Gunson recommend that you not exceed 20psi and I actually blew a reservoir off the master cylinder once by trying to force things! so I think if it can stand around 35psi it's going to work just fine.

Now I have the problem of adapting the original caps, which came with the kit when I bought it many years ago, so I can use them when I don't, or can't, use the universal one. I've already sorted out some suitable bits and pieces but just ran out of steam to do anything much with them:





Maybe tomorrow? At least I'm now prepared when I get my hands on the Jazz again. Discs and Pads are waiting eagerly under my workbench. Just hope the calipers wind back nicely - but, on an 11 year old car, maybe I'm being too optimistic?

 

[Pugglt Auld Jock]

I left the original entry "hanging" a wee bit because I hadn't completed adapting the original cap adaptor to fit the new end of the pipe from the pressure vessel Hopefully the following pictures will help clarify what I mean by that.

I got as far as this with it before breaking off:



Now my brain is rested I've changed it a little bit from my original idea which would have involved two cable tied connections. It now has only one and the new bit is soldered to a short length of brake pipe which is secured into a connector suitable for the taper type connector on the universal cap I've already made:





To change over from one to the other all that has to be done is slacken that big nut on the top of the universal adaptor and screw it onto the end of the one I've just completed. You can see that the seal is made by the tapered end on the connectors - I've included a spare connector in one of the shots so you can see how the tapers go together. I do wonder how often I can swop them over before the taper fails to seal? But as I'm only using this on an occasional basis maybe it'll outlast me?





It has just occurred to me that some people may not be familiar with bleeding brakes in this way (the traditional method is by pumping the pedal but this runs the risk of master cylinder seal damage if the cylinder is not fairly new). So to avoid that you can either suck the new fluid through from the cylinder/caliper end (bleed nipple) or force it through from the master cylinder end. I've tried my pal's suction device and I found that air tended to get round the threads of the bleed nipple so you got air showing in the bleed tube which made it difficult to see when there was no more air in the actual system. Many years ago I bought a Gunson Eezibleed. - which is about the cheapest way into pressure bleeding:



I find it works very well. It works by you selecting a suitable adaptor to fit the master cylinder reservoir (in place of it's cap). Then, very importantly, you pressure test for leaks by connecting the air adaptor (looks like a tyre inflator connector) on the end of the black tube to a car tyre (with pressure reduced to around 15psi) - so I use my spare. Hopefully you'll find no leaks so you then disconnect the tyre connector relieve the pressure, take the top off the Gunson pressure vessel and fill with new brake fluid, and screw the top back on. When you are ready to bleed you just get your bleeding tube onto the cylinder/caliper you are working on, connect up the tyre again and open the bleed nipple. The fluid/air is driven through by the air pressure in the pressure vessel and when clear fluid emerges (just as when bleeding with the pedal) you nip up the nipple and you're done. It all packs away very neatly into an old ice cream container for storage.



I notice Sealey seem to be doing a virtually identical tool Sealey VS0205 Automatic Brake & Clutch Bleeder: Amazon.co.uk: Amazon.co.uk: and there are other contenders at greater cost. An ebay browse will reveal all I'm sure.

The only trouble I've had with mine is that the pick up tube in the pressure vessel has fallen off a couple of times which is very annoying as you then end up with air being pumped in instead of fluid! It was very easily fixed with a cable tie:



Where would we be without cable ties.

 

[portland_bill]

Many years ago I had a friend with a Gunson Eezibleed. It was one of the few things that would bleed a Marina clutch successfully and did make bleeding brakes a doddle.

It did seem to result in the car reservoir becoming filled to the brim, which became very messy when removing the cap, as there was too much fluid. For this reason, I went the vacuum route, with a small hand operated vac pump and tiny reservoir to catch the bled fluid. This also has a downside, in that air is pulled in past the bleed nipple threads. Removing the nipple and wrapping the thread in plumbers PTFE tape can help, but not always successful.

Before bleeding, I tend to open the nipple and leave it with a tube inot a jar for a short time. Gravity tends to get the fluid to flow, bringing the air with it, so once ready to bleed, little work is needed. This seems to work well even when hoses, pipes or cylinders are replaced.

Still hate the job though, although returning to cable or rod like the 1930s might not be the way to go.

 

[Pugglt Auld Jock]

It did seem to result in the car reservoir becoming filled to the brim, which became very messy when removing the cap, as there was too much fluid.

Before bleeding, I tend to open the nipple and leave it with a tube inot a jar for a short time. Gravity tends to get the fluid to flow, bringing the air with it, so once ready to bleed, little work is needed. This seems to work well even when hoses, pipes or cylinders are replaced.

Still hate the job though, although returning to cable or rod like the 1930s might not be the way to go.

You're right PB, it does tend to leave you with an overfull reservoir. Once you know this you can make allowance with a catch can and copious quantities of rag/paper towel. However it's not ideal. I'm trying to figure out how to add an extension to the cap/universal adaptor such that it sticks down into the cylinder reservoir by, say, maybe an inch. Then removing some fluid before you start so that the level is below the end of this tube. I think that what would then happen is that although the air in the top of the reservoir would be slightly compressed (we're only talking 15psi here) it would remain trapped in the top of the reservoir so that when you removed the bleeder you'd still have something of an air gap? Also it has just occurred to me that disconnecting the air supply with this small tube in place would cause some fluid to be chased back up into the Eezibleed reservoir and if the Eezibleed was lower than the master cylinder the residue in the pipe would drain by gravity/syphon back into the Eezibleed? Anyway, worth experimenting with I think. Maybe some sort of a tap in the feed tube to the reservoir adaptor so you could turn it off before loosening the adaptor so no extra fluid drains into the reservoir? I get the feeling my experimentation is not yet completed! I've also been thinking of making one using a pump up plant sprayer then I wouldn't need to involve that spare tyre. I feel a winter project coming on!

And again, just like you, I find letting things bleed out by gravity for a few minutes before trying to force things definitely pays dividends. In fact on short run pipes it does a pretty good job on it's own. I also have to agree it's not one of my favorite jobs either. I always seem to end up with fluid getting somewhere it shouldn't and I stress out about the possibility of damage to paintwork.

 

[s130]

Have just bleed the brakes on our B using just the Easybleed bottle as a nice catch reservoir only. Helps you keep an eye on the topping up requirement to ensure you don't pump air into the system.

Bought Easybleed many years ago and had all sorts of problems getting a decent cap to reservoir seal. Horrible result of fluid welling out all over the place. Never again. Only now trust pedal pushing.

As for the reservoir with you system get filled to the brim you need to change the design.

You need to add length of tube that drops down into the reservoir. When the reservoir fluid level reached the end of the tube then the level should only climb up a small/medium amount dependent on the feed pressure and the reservoir free space volume.

Even the slightest air leak will be brake fluid tears everywhere

 

[DaveMcT]

I use the Fuzz Townshend method when I change the brake pads. Open the bleed nipple push the piston(s) back close the bleed nipple. This clears out the old mucky fluid and it can be repeated if you top up the fluid and pump the pistons out again.