Cycling UK Forum

Samuel D wrote:I have a Zefal HPX that leaks around the head area (not exactly sure where). It did this from new, but due to particular circumstances I couldn’t return it. Would it be worth my while trying to find a way to remove the head and attempt a fix? I believe I would need an extremely long screwdriver to do this (hence my not having done it yet).

Is it from an area you could get grease into?

The head is meant to be assembled for your valve type. Have you got that right? There is a cylindrical rubber insert that can be reversed (presta/ schraeder) and a plastic insert for shraeder. If you assemble these two bits incorrectly you will get air leaking. Sorry if I'm pointing out something you already know.

Oh, you’re right to question whether I’m doing things right! However, I think I am. I’ve seen this type of convertible valve before, and I also followed the Zéfal instructions carefully.

The air appears to leak from the junction between head and pump barrel. However, the head is tightly attached, so I don’t think it’s just a question of tightening the screw inside the barrel. Maybe there is a burred edge or improperly positioned gasket preventing a good seal? I’m just guessing. The leak is large.

What method do people use to undo the screw at the end of the barrel? I have never seen a screwdriver long enough.

I thought mine was leaking between the barrel and head to start with but it turned out to be the slider seal.

Therefore I'd suggest that you remove all the gubbins from the head (it all comes out) and then block off the port with something (eg your little finger or a piece of blu-tac). Then and only then remove the head if there genuinely is a leak between the barrel and the head.

If yours is like mine, it would seem that when the lever on the chuck is moved to the 'closed' position, the slider seal goes a little bit too far and then there is a leak in the head.

hth

cheers

Is there any bicycle-related problem you haven’t come across, Brucey? You were right! When I remove all the gubbins from the head and block the port that is revealed (my little finger just about fits from one side), there is no leak.

So the leak is in the gubbins somewhere. The rebuild kit doesn’t include all the gubbins. My pump seems generally well made, but perhaps it has an unlucky combination of tolerances in said gubbins.

That said, the head components are heavily greased. I’m tempted to clean it up a bit and try again, but I have no suitable grease with which to re-grease it if I go too far.

Well, well, well. I went ahead and removed the thick layer of grease, and in the gloop I found a small metal filing. Of course I removed it.

When I put everything back together again, the pump worked! No leak. If only I had known fixing it would be this easy. Thanks for prompting me to take a look at it, Brucey.

good work fella!

glad you fixed it!

cheers

Samuel D wrote:Well, well, well. I went ahead and removed the thick layer of grease, and in the gloop I found a small metal filing. Of course I removed it.

When I put everything back together again, the pump worked! No leak. If only I had known fixing it would be this easy. Thanks for prompting me to take a look at it, Brucey.

you should still think of getting something like a Mt Morph - much easier when it really matters

mercalia wrote:you should still think of getting something like a Mt Morph - much easier when it really matters

How easy does it need to be, though? I can cope with a bit of pumping effort (and sometimes like the warmth that provides by the roadside) as long as the pump can reliably achieve a decent pressure. Too many portable pumps cannot!

Samuel D wrote:

mercalia wrote:you should still think of getting something like a Mt Morph - much easier when it really matters

How easy does it need to be, though? I can cope with a bit of pumping effort (and sometimes like the warmth that provides by the roadside) as long as the pump can reliably achieve a decent pressure. Too many portable pumps cannot!

Whilst I think the Mt Morph style of pump is easier to use, the Zefal HPX would be my second choice of pump to get stuck with if I had a flat on a dark lane, in the rain. And the HPX can be still in working order well after a decade. So I would not recommend ditching the HPX. But if you ever buy a bike that the HPX does not fit, that would be a time to consider a Mt Morph or similar.

If you want a pump that is going to last, get a Zefal HPX or something. I'm sure that there are any number of pumps that are a little bit easier to use, but most of them just don't look made to last to me, and have some pretty glaring design faults.

Taking the mountain morph for example;

- the while thing contains many sticky-out plastic parts that are certainly going to be vulnerable to breakage.
- only a few spare parts are available (better than many other pumps but still not good enough IMHO)
- the bracket they suggest you use positions the pump on the bike where it will collect absolutely the most road crud possible
- the pump has many places where ingress of crud will quickly stop if from working
- the pump is so badly designed that if it should rain when it is strapped onto the bike, it can fill up with water...

So as a pump it might be easy to use whilst it is working but as a product it doesn't really seem built to last, and if you used it as intended (i.e. strapped to the bike in all weathers) I think it would very quickly fail. Definitely one to keep in the pannier, I'd say.

BTW if anyone finds a pump 'hard to use' and wishes it would brace against the ground, you can probably add a flexible hose to it. The only requirement is that the pump ought to have a check valve in it, which most pumps, (certainly all that fit Schrader valves) do these days. Any hose and connector (spare part for a track pump) can have an old valve body fitted to the end where it goes into the pump et voila you have a 'mini track pump'.

cheers

I have ordered one of those nice Lezyne micro floor pumps (high pressure version with gauge) for my wife to use on her commute, so when it arrives I will do a comparison test with one of my Zefal HPX frame fit pumps. I will count the strokes to get to a specified pressure, and offer some subjective impressions about ease of use and build quality.

(I will ensure valve cores are nice and tight before testing because I understand the screw-on Lezyne attachment can cause loose cores to unscrew)

I look forward to your report, pwa.

I realised I have some of the pumps mentioned in this thread, with a motley collection of various mini pumps that have largely not proved that good or failed.

So here are my test results below. I used a Continental GP 4 Seasons 25mm on a Mavic Open 4CD rim, pumped up to 90psi. Only the 2 track pumps have gauges so I checked the pressure by feel and confirmed with the Lezyne track pump.

What was surprising was how easy the Lezyne Micro Floor Drive HP Mini Pump was, it feels smooth and easy, when you need to push more positioning yourself over the pump and using 2 hands on the pump was comfortable and not too much effort. One of my daughters could manage, she also can use the 2 track pumps, but none of the others would be practical for her. Only got this a few months ago and hope it lasts and doesn't corrode and proves reliable. Yes, screwing in the Lezyne head is a pain, slow and sometimes it doesn't thread on straight.

The Zefal HPX, unfortunately doesn't fit the frame I intended it for, too long and also too large a diameter for the pump peg below the top tube. In use this pump was ok but took a lot of force with both hands required, one pushing and the other needing a lot of effort to resist the force. Twice the head slipped off the valve.

I didn't try any other mini pumps other than my Topeak as that was bad enough. It is a genuinely useful pump that I carry on rides, I have had to use it in anger after punctures and it is a pain. Needing sometimes close to 300 strokes, both hands together, gripping the pump between the feet and stopping to let the base cool off a couple of times. But it can attain useful pressures.

A few mini pumps I have collected. The Bontranger one (centre) feels well made, but when I needed it the end just split. Luckily I was only 3 miles from home and walked back in my socks as I was using Look pedals. The shop replaced it without question, but I won't trust it.

The Lezyne (right) is the best but is also the biggest, my calf can just feel the pump at times when mounted on the seat tube.

2nd right is the Topeak and this is my next favourite, works well but is hard work to get to full pressure. Also fills with water, but I suppose all of them would eventually.

If travelling a long way from home with panniers I will take 2 pumps.

I will be interested to see pwa's test and how it matches with my experiences.

Des49 wrote:I didn't try any other mini pumps other than my Topeak as that was bad enough. It is a genuinely useful pump that I carry on rides, I have had to use it in anger after punctures and it is a pain. Needing sometimes close to 300 strokes, both hands together, gripping the pump between the feet and stopping to let the base cool off a couple of times. But it can attain useful pressures.

Genuinely useful...300 strokes? Sounds like an exercise in masochism to me.