Hi I have the 228 shocker series horn kit. It worked fine for about 6 months with no problems. Now every time I use them when the tank is full the horns squeak then when the pressure lowers it sounds normal. I drain my tank 4-5 times a week. and was wondering if maybe its the solenoid? I don’t know if its a filter inside there but whatever it is, is glazed over and brownish colored. Would changing that mat a difference? What would be causing my horns to squeak only at peak pressure but when the pressure lowers a little it goes to sounding normal? thanks
Sounds like the diaphragms to me… what psi are you running?
Also any chance u had a big rain and theres water sitting in the horns?
im running 145 psi. it wouldnt be rain they are hidden behind my bumper and is pretty waterproof behind there. you think new diaphragms would make it function correctly?
just looked and couldnt seem to find any diaphragms for sale for my particular horns.
Contact HB via phone or email.
thanks, i will defiantly do that tomorrow
I have posted about having a similar problem like that in another thread.
http://www.trainhornforums.com/showpost.php?p=56973&postcount=6
Okay, I’m re-upping this…
I just fixed my horns this afternoon and they were having the same exact problem you’re having.
^^^^^^ that is an extreme case where something got inside the horn and caused damage.
I have the rocker horn kit, which uses the same horns that come with the Shocker and HB4H kits…but uses the 2 smallest horns. When the squeaking started it sounded like was a dying animal…but it sounded more like it wasn’t getting enough air pressure…
so, I disconnected the hoses to the horns to check the solenoid. Once the tank was full I tested it…thinking maybe my $2.50 RadioShack honk button was a POS or the solenoid wasn’t opening all the way…
…and everything was fine 
So, I went back to the horns.
Turns out the tuning screw had backed out due to the EPIC LOUDNESS 
lol, and was allowing air to leak past the diaphragm before it had a chance to vibrate.
Buying replacement diaphragms is never a bad idea, but before you decide to send the horn back or tear it apart, just try tightening the tuning screw on the back of the horn about a 1/4 turn in. If it still squeaks, tighten it a little more but do it in small increments until it sounds like it should.
Hope this helps! 
hmmm I guess that explains why my problem never fully fixed. it works fine for a couple weeks or so then the problem repeats. After re-tuning, it sounds ok but just for another couple weeks. The tuning screw is rather tight but I guess honking it everyday (drivers here need to be waken up) might be enough to back it out.
I’ll try superglue on the outside (just a drop to lock it in) and see what will happen.
It’s late but welcome to the forums “krayz”
Try using Loctite first instead of super glue.
I have loctite but I’m not sure if it will stick as it is designed for metal to metal contact and the horns are metal to plastic.
seems like my reply didn’t get through.
I took the horns out again this afternoon and checked each horn and indeed the tuning changed (just after 3 days of use!!)
I have loctite but I think it was designed for metal-metal contact so I used a drop of superglue around the screw. It is just at the outside so it can be removed if necessary. Time will tell if it will work.
yea, I’m not sure if loctite is going to work well enough.
You could try using Car/truck silicone (the black stuff). It’ll dry into this rubbery substance that sticks to anything and more importantly it can be pealed off later if it needs to be fixed.
This is actually for making gaskets on cars but it should work perfectly.
Careful about adjusting the setscrew for the horns… I believe HB VOIDS warranty once you alter the calibration…
I’m in another continent so sending it in and back for warranty would cost about the same as a new set of horns so tinkering with it is my only option besides getting a new set.
…If that’s the case I want to know why mine became UN-calibrated after only 2 weeks.
I don’t even drive my truck everyday to be able to use them a lot…just doesn’t seem fair to me!
plus, I’m not the only one who’s had this happen.
I spent $400 on a horn kit that “broke” after only 2 weeks…it shouldn’t have broke at all.
But for hornblasters to void a warranty because you decided to fix a problem they didn’t deal with initially or just happen to look over…That’s not right!
I could understand if you completely took them apart…that’s one thing. But to use the tuning screw that was designed to be used with the horn allowing you the option of higher or lower pitched horns…and have that void the warranty…that’s a really good way to lose your customer/fan base.
But that’s just my opinion
I’m just giving advice from what i read in the past…
Oh okay…and sorry, I didn’t mean to come off as an a$$.
Thanks for the input