More problems

[Welder Dave]

I ordered the slave cylinder from Quebec and it finally came but was a day late. OK, at least I have it. I open it up and notice 1 of the ports is a larger size than the other. I try my 1/8NPT fitting in the smaller hole and it won't go. I'll just go and get the proper fittings/adapters for the brake hose and a differentvthread bleeder. I went to 3 different places and they couldn't match the threads to anything. 1/8"NPT is close but the threads are 20 tpi and just a little small. The larger port is also about 20 tpi and a little small for 1/4"NPT. Being Friday it's too late to get a response back from the supplier. If the warranty would still be honored I was thinking of retapping the threads for NPT using brake fluid as a tap cutting oil. I'd also want a partial refund to cover the cost of buying taps and retreating the slave cylinder. I guess the 1st thing is to see if I just got a bad part but if they're all the same would it be better to send it back on their dime or if they would still honor the warranty (that it works properly) and offer some discount, rethread it and make it work? If I could get $50-$100 off wouldn't be too bad. A rebuilt one is about $130 more before any discount for having to modify the replacement. I am so pi$$ed off. If it would have at least got here on time I could have got an answer today what they would do.

 

[Diesel Dave]

1/8 NPT 27 TPI measures .405 “ OD.
7/16“ fine thread 20 TPI measures . 0.438“ OD.
1/2“ fine thread 20 TPI measures .500” OD.
1/4 NPT 18 TPI measures .540” OD.
To avoid any potential liability there is NO way your supplier will want to get involved in modifying their component.
I’m sure the supplier will offer to ship the proper adapter fittings or if you are in a rush provide the part numbers so you could locate them in western Canada.

 

[OzDozer]

Send it straight back, they've provided an incorrect part, if you gave them the correct part number.

You start into a minefield as soon as you start cutting new threads.

 

[Welder Dave]

I already asked if they had the bleeder and elbow and gave the OEM part numbers. They didn't have them and even if they did wouldn't fit. I can check if they are bolt threads but then there are no adapters for a bleeder or an elbow with an inverted flare. If they are bolt threads how do get them to seal for pressure? Also if 1/8" NPT is too big there's no way a 716" fine thread would fit.

 

[OzDozer]

Parallel threads, as in bolt threads, normally seal with a copper washer. But if you can't ID what thread is currently there, you're up against major problems to start with.

 

[Welder Dave]

Send it straight back, they've provided an incorrect part, if you gave them the correct part number.

It is an aftermarket slave cylinder but the bag says Volvo and has the correct part number. I don't want to get stuck paying for return shipping. I'm going to see if the threads for the swivel joints fit. I don't have them at home. I don't want to have to pay another $127 for a rebuilt one but may have to. I was thinking if I got a decent discount and they'd give warranty if the internals leaked I could make it work. I'd have to be really careful rethreading it and cleaning all the filings out. Would be best to take it apart but probably not worth it. Damn it anyways!

 

[Welder Dave]

Parallel threads, as in bolt threads, normally seal with a copper washer. But if you can't ID what thread is currently there, you're up against major problems to start with.

The holes are straight through the cylinder so no seat for copper washers unless they fit under the head. Then I'd have to thread a bolt to make an NPT adapter. I can only hope I got one where they screwed up the threads. If that's the case they should send a new one priority shipping and a prepaid return label.

 

[1693TA]

See if this will be of any help to determine what threads you have:

Thread Type Guide: NPT, BSP, JIS, SAE, Metric – Trimantec

So you finally found the right solenoid valve to replace your broken one. You call to check stock on the item and the sales rep asks you what thread type you need. You ask, “How do I find out what thread type I need?” Fortunately, we’ve got you covered.

trimantec.com

 

[Welder Dave]

I'm pretty sure all the thread sizes were checked at the 3 places I went. A hose and fittings shop, a brake and clutch shop and a specialty hyd. shop that deals in metric and european fittings in addition to more commonly used fittings. SAE threads were close in size but wouldn't thread in and there's no taper for them to seat. These are just really odd threads. The easiest way to possibly make the slave work is to thread it to NPT. It would be good if the supplier could check their other stock and see if they all have the oddball thread and/or find fittings that fit.

 

[1693TA]

Post up photos and part numbers of what you are working with and where it goes if possible. I have some contacts versed in the equipment I can run them by and see if it will do any good. If you have the old slave cylinder still include some measurements. I can get you a cylinder made if need to go that far.

You get Volvo in the middle of any large operation and it WILL get fucked up. Standard operating practice it seems. Look what they did to Mack Trucks as example. You are suffering the same fate with your older equipment we did.

 

[Welder Dave]

The slave is aftermarket but the right part number. The problem is the ports are threaded wrong. So wrong that they don't fit any common fittings. I don't have the original at home but it has both ports as 1/8" NPT. In the pics. below the small port is just a tad too small for 1/8" NPT and the large port is a tad too small for 1/4" NPT. The thread pitch is also wrong. I can get a rebuilt OEM slave but it's about $925 with tax. I think the threads could be retapped so they would work with the fittings I need. However I would need to be assured that the rest of the slave is still covered by warranty and be compensated for the expense to retap the threads. It wouldn't be good to have the slave leak or not work properly after going to the trouble of retapping it. It would be best to take it apart to fix the threads. I don't know if there's special precautions to taking apart and putting the slave back together? Perhaps a refund of $75 or more would be worth making the slave work?? If no discount or warranty it would be better to just get my money back and buy the rebuilt one. I also would want the shipping it back covered.

 

[Vetech63]

#4 o-ring thread?

 

[Welder Dave]

The last shop said maybe an SAE 4 or maybe it was 5 for the larger port but those use a flare. Being it's machined flat could make sense for an o-ring fitting but being it's for brake fluid would eat standard o-rings. I thought maybe a fitting that uses a copper washer like a drain plug but it can't be common that no one carries them. Both ports look to be 20 threads per inch. I'll do some looking online. Another thought I had was a machine shop could make adapters that thread in the holes and convert them to 1/8" NPT.

 

[DMiller]

Those sure appear as a Banjo Style with Seal Washers ports.

 

[Welder Dave]

There's not much flat area around the ports. I'll check out bango fitting thread sizes. If I could find something that threads in I could probably make adapters from those and seal them with Loctite 577 for straight threads.

 

[Simon C]

In post #8 there is a chart on JIS thread versus NPT . You will see that 1/8 NPT is OD 10.3mm versus the JIS 1/8 thread OD that is only 9.4 mm.
I run in to this all the time on Komatsu equipment. Maybe one of the JIS threads would fit. Where are you in Alberta by the way.
Hope it helps
Simon C

 

[Welder Dave]

I'm in Edmonton. Looking at threads banjo bolts come in 3/8" 20 and 7/16" 20. Maybe they would fit but how do you adapt to NPT? If I could find some bolts to fit maybe adapters could be made?? Another thought was plug the holes and drill new holes for 1/8" NPT. Of course if the supplier won't compensate me for having to modify it, it's better to just send it back. I thought maybe NPT half couplings could be welded on but then I'd have to get it honed. Adapters would be better and I wouldn't have to take it apart.

 

[Welder Dave]

The supplier called me first thing this morning. He said to let him know how much it will cost to modify the slave and would offer a discount to cover it. I'd guess with in reason and he said it would still be covered by warranty. I could also return for a full refund including shipping. I think that's the best any supplier could do. I'm not too happy it isn't a direct bolt on but hopefully I can get it to work in short order.

 

[Welder Dave]

I finally found out what the threads are supposed to be. SAE 3 and SAE 5 o-ring but the #5 had the first thread buggered up that a fitting wouldn't thread in. To use these threads I would need to get different o-rings and then a couple more adapters on each to get to 1/8" NPT female. The hyd. shop agreed it would cheaper and easier to just weld some NPT ports over the existing holes. I got some forged weld fittings or $10 and after I take it apart I'll take it to a Tig welder I know. I could probably weld it but it's a little cold out and they are pretty small for stick welding. Tig would be easier and look better. I had to buy some snap ring pliers and I bought a clamp but the clamp I can use for other stuff. I don't think the welding will cost much so I'm thinking of telling the supplier about $100 to modify it. The hyd. shop said it would be $135 to retap the holes but then I'd also need to fill the old holes.

 

[Welder Dave]

I took the new slave apart and there sure isn't much to it. The machining in the bore and overall quality looks good. Everything was tight. The thread for the eye bolt had slight damage but it will clean up by running the eye bolt in and out a couple times. The old one everything is sloppy and flops around. I didn't take it apart. Still don't understand why they are so expensive especially the rebuilt used one I could have got locally.