Home / Repairs / Hydraulic ram rebuild

Our signature repair · Arncliffe, Sydney

Convertible roof hydraulic
ram rebuilds, Sydney & NSW

Oily residue behind the rear seats. A roof that lifts slowly, or sits lopsided halfway through its travel. That's the seals inside a hydraulic ram letting go, and the dealer answer is usually a complete new ram, at an eye-watering price, on a long lead time. Ours is different: we rebuild your original rams. It's been a core specialty here for over twenty years. And if you're in or near Sydney, you don't have to remove a thing yourself: drive the car in and we remove, rebuild and reinstall the rams, then cycle- and water-test the roof before you collect it.

20+ yrs in automotive repair 1000+ roofs serviced 4.9★ Google rating

Call about hydraulics Submit an enquiry Submit an enquiry

The rebuild, explained

Why your rams fail,
and why we don't bin them

A hydraulic roof is a small, hard-working system: a pump, a set of lines and several rams doing the lifting. Here's how it ages, and what a proper rebuild actually involves.

Part 01

How a hydraulic roof fails

Seals age. Steel doesn't.

Inside the ram

Each ram is a steel cylinder and piston, sealed by rubber that lives under pressure and heat for the life of the car. The cylinder is good for decades. The seals aren't, they harden, shrink and let fluid weep past every time the roof asks for pressure.

What you notice

It starts subtle: a roof a second or two slower, a hesitation at the top of the lift. Then oily drips behind the rear seats or in the boot, a roof rising lopsided because one ram is doing more work than its partner, and finally a roof that stalls partway.

What it isn't

Owners get told it's "the motor" or "the module". Sometimes it is, which is why we diagnose the whole system rather than guessing at the loudest part. Fluid where it shouldn't be, though, is seals. There's no software update for rubber.

Describe your symptoms Submit an enquiry Submit an enquiry

Part 02

Rebuild versus replace

The quote nobody offers you

The dealer path

Many dealers only sell complete new rams, often at eye-watering prices, on long lead times, and per cylinder when a roof carries several. The part is dealer-only on plenty of models, which is exactly why the quotes look the way they do.

The rebuild path

We take the path the dealer doesn't: your original rams come out, get rebuilt with new seals, and go back to doing their job to spec. Same cylinders, fresh rubber, working roof, backed by the same parts & labour warranty as everything else we do.

When we won't

Honesty cuts both ways. If a cylinder is scored, corroded or bent (rare, but it happens) a rebuild isn't the right call and we'll tell you so before quoting, with the part in your hand if you want it.

Get a second opinion on a ram quote Submit an enquiry Submit an enquiry

Part 03

What the rebuild involves

System job, not a seal swap

Diagnose first

Before anything comes apart we confirm it's actually the rams: electronic diagnostics on the roof's control system, then a hands-on check of which cylinder is weeping and how the pump and lines are holding up. You see what we found before a quote is written.

Rebuild properly

The cylinders come out and get rebuilt with new seals, and we inspect the lines and pump while the system is open. There's no point fitting fresh seals downstream of a tired pump. Then the system is flushed, refilled and bled.

Prove it works

The roof gets cycle-tested (up, down and up again) until it runs at full speed, square and silent. Hydraulic work leaves on results, not promises, with the workmanship warranty behind it.

Book a diagnosis Submit an enquiry Submit an enquiry

Part 04

Pump, cylinder, hose or microswitch?

Rebuilding the wrong ram won't fix your roof

Mercedes SL & SLK

The vario-roof runs a set of cylinders working in sequence, and they rarely fail alone: the seal compound that's let go in one is the same age in its neighbours. We assess the whole set, not just the cylinder that's weeping into the boot, so the rebuild doesn't get repeated one ram at a time.

BMW Z4

The Z4 hardtop is the classic pump-versus-cylinder call. A roof that's lost pressure can mean tired ram seals, or a pump and micro-switch fault that no amount of new rubber will cure. We test the pump's output and the switches before a single cylinder comes out, because the wrong answer here costs you the whole job twice.

Audi A4 & TT

Audi's cabriolet ram seals age into the textbook slow, lopsided roof, but a chafed hose or a flap sensor can mimic them. Is it the pump, a cylinder, a hose or a microswitch? That's the question we answer with diagnostics and a pressure check first, then show you, then quote.

Get the right diagnosis first Submit an enquiry Submit an enquiry

Part 05

Rebuild locally, or mail your rams overseas?

Count the whole cost before you post

What mail-in really involves

There are overseas outfits that rebuild cylinders well, by post. Read the fine print on what that asks of you: remove the rams yourself or pay a workshop to do it, drain and contain the fluid, pack and freight them overseas, handle the customs paperwork and any duties, then wait the weeks it takes for them to come back, with your roof inoperative the whole time.

Where the warranty lands

A mail-in warranty covers the parts. It doesn't cover the labour to remove and refit them, and it can't cover the question that matters most: was it actually the rams? If the real fault was the pump, a hose or a microswitch, your freshly rebuilt cylinders come home to a roof that still doesn't work, and nobody owns that outcome.

Local? We fit them for you

A convertible roof hydraulic ram rebuild done here in Sydney keeps the car, the diagnosis and the rebuild in one NSW workshop. If you're in or near Sydney you don't lift a finger on the car: drive it in and we remove the rams, rebuild them on our own bench and reinstall them, then cycle- and water-test the roof before handover. One job, one warranty, one phone number if anything's ever wrong.

Compare it for your car Submit an enquiry Submit an enquiry

Where we see it most

The roofs that keep
our seal bench busy

Four badges account for most of the rebuilds on the bench in any given month.

Mercedes-Benz: SL and SLK vario-roofs are the classic case: sets of hydraulic cylinders weeping fluid into the boot, discovered when the luggage comes out oily. We rebuild them as the set they fail as.
BMW: Z4 hardtops where the real question is pump or cylinder. We test the pump and micro-switches before any ram comes out, so the rebuild fixes the actual fault.
Audi: A4, A5 and TT cabriolets with ram seals past their best, the textbook slow, lopsided roof, nursed along a year too long.
Holden: Astra and Cascada convertibles whose hydraulic systems are simply overdue a rebuild. They're at the age where seals give up in numbers.

Jaguar latches, Infiniti hardtops, something else hydraulic? We work on most makes: text us the make and model or call 0418 200 289.

How a visit works

Four steps. No surprises.

1
Tell us what it's doing

Call 0418 200 289. A short video of the roof moving, plus a photo of any oily residue, usually gets you a first read the same day.
2
We diagnose, you see it

Electronic diagnostics plus a physical inspection of rams, lines and pump. We show you which cylinder is weeping before anything is quoted.
3
We rebuild to spec

Your original rams, new seals, system flushed and bled, by factory-trained technicians. Nothing happens without your go-ahead on the quote.
4
We rain on it before Sydney does

The roof is cycle-tested until it runs square and at full speed, then water-tested before handover: seals soaked, cabin checked dry. That test is why the warranty isn't a gamble for us.

Straight answers

Hydraulic questions
we hear every week

If yours isn't here, call. You'll get the same straight answer.

Ask us directly Submit an enquiry

Why rebuild the rams instead of fitting new ones?

Because for many roofs, new rams are a dealer-only part with a long lead time, and the cylinder you already own is usually mechanically sound. It's the seals that have aged, not the ram. Rebuilding fits new seals to your original cylinders and returns them to spec, backed by our parts & labour warranty. Where a rebuild genuinely isn't the right call, we'll say so before quoting.

Is it safe to keep using the roof while it's leaking fluid?

Best not to. Every cycle pushes more fluid past the failed seal, and a system running low works the pump harder for less result. The roof that's slow today is the roof that stops halfway later. Park it closed if you can, and call 0418 200 289 before cycling it again.

How do I know it's the rams and not the pump or a sensor?

Often you can't from the driver's seat, and that's the honest answer. Oily residue plus a slow or lopsided roof points strongly at ram seals, but a tired pump or a sensor can look similar. We diagnose the whole system and show you what we found before anything is quoted.

Will rebuilt rams just leak again?

Not if the job is done properly, which is why we don't just swap seals and hand the car back. Cylinders are inspected, lines and pump checked, the system flushed and bled, and the roof cycle-tested before handover, all covered by our parts & labour warranty.

I'm near Sydney. Do I have to remove the rams myself?

No. Removing the rams yourself is only for the mail-in service. If you're in or near Sydney, just drive the car in: we remove the rams, rebuild them on our bench and reinstall them, then cycle- and water-test the roof before you collect it. One workshop owns the whole job, from diagnosis to a working roof.

Why not just post my rams overseas to be rebuilt?

You can, but count the whole cost first. The mail-in route means removing the cylinders yourself or paying a workshop to, draining the fluid, freight both ways, customs paperwork and duties, and typically weeks with the roof out of action, under a warranty that covers the parts but not the labour to remove and refit them, and never the diagnosis. Rebuilding locally keeps the car, the diagnosis and the rebuild in one Sydney workshop, with the roof cycle- and water-tested before handover.

Do you rebuild Mercedes SL/SLK, BMW Z4 and Audi TT roof hydraulics?

Every week: they're the regulars on the bench. SL and SLK vario-roof cylinders fail as a set, so we assess the set; the Z4 is the classic pump-versus-cylinder call, so we test the pump and micro-switches before any ram comes out; A4 and TT ram seals age into the textbook slow, lopsided roof, but a hose or sensor can mimic them. Rebuilding the wrong ram won't fix your roof. That's why the diagnosis always comes first here.

What owners say

From the 4.9★ Google reviews

★★★★★

"Michael is the best. My Benz had a seized panoramic sunroof and the motor for the roof died. He had it fixed and working perfectly in three hours. And was by far the most reasonably priced."

Mercedes-Benz · Seized panoramic sunroof & motor

★★★★★

"It was an absolute pleasure dealing with Michael. With 29 years of experience, he really knows his craft. He was honest, friendly, and did a perfect job fixing the convertible top on my Mercedes. Definitely worth the 1-hour drive to get there. Highly recommended!"

Mercedes-Benz · Convertible top

★★★★★

"Michael is an amazing craftsman. For what would have taken us to get an entire large part from BMW and coordinate roof repair with expensive repair service, Michael created a small part for our car and fixed it then and there. He charges reasonably. I highly recommend his service and will happily be a repeat customer."

BMW · Roof repair

Visit the workshop

Bring it in, or start
with a text

Address: 54/58 Princes Hwy, Arncliffe, Sydney NSW 2205, minutes from Sydney Airport
Call: 0418 200 289
Email: [email protected]
Hours: Mon–Fri 9am–6pm · Sat 9am–4pm · Sun closed
Instagram: @convertiblesunroofautocentre

Start an enquiry

A few details so we can tell you whether it's a job for us and how we'd approach it. By appointment; for most faults, we diagnose before quoting. For urgent enquiries or if we missed you — call 0418 200 289.

Name * Email * Phone * Location * Car (make, model, year) * How can we help? *